an autodidact meets a dilettante…

‘Rise above yourself and grasp the world’ Archimedes – attribution

leadership, thugs, hormones, bonobos, oxytocin and the future: an interminable conversation 2

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just a bunch of female leaders, circa 2018

Jacinta: So, in pointing out that, according to the democracy index, female leadership and some of the best democracies go together, I didn’t mention the fairly obvious chicken-and-egg issue. Does quality governance lead to more female leadership, or does female leadership lead to better quality governance?

Canto: Isn’t this called a synergistic effect? So it’s not quite chicken-and-egg. Or is it?

Jacinta: No matter, you’re right. The term’s generally used in science – here’s an overly-complicating definition from one scientific paper:

Synergistic effects are nonlinear cumulative effects of two active ingredients with similar or related outcomes of their different activities, or active ingredients with sequential or supplemental activities.

You need to learn that – it’ll be in the test.

Canto: The idea being that female leadership and good governance result in more than the sum of the two parts.

Jacinta: Well, when I wrote about the democracy index, I found that the countries near the top of that index, the best democracies, were top-heavy with female leadership, by which I meant Prime Ministers and Presidents, but I didn’t look more closely at the social make-up of those countries – the predominance of female business leaders, scientific team leaders, the percentage of women in other political or governmental posts and so forth. I made the perhaps reasonable assumption that those countries are also leading the world in every kind of leadership position for women.

Canto: To be fair, researching all those things for each country would be quite a job. We don’t get paid for this shit. I think we can at least assume that those Nordic gals are pretty formidable. Northern European countries feature heavily in the top twenty. Even the UK gets in there.

Jacinta: Australia squeezes into the top ten. And will only improve with the new diversity in government after the recent election. And the most women in our parliamentary history.

Canto: So, as this female empowerment continues apace, at least in the WEIRD world, what will this human world look like, in the 22nd century?

Jacinta: Well, it could be – and this wouldn’t surprise me – that the macho world, run by Mr Pudding, Mr Pingpong and their enablers, and possibly their successors, will do catastrophic things before the turn for the better, because out of catastrophes – the two world wars of the twentieth century, the holocausts in Europe and Africa, Hiroshima and Nagasaki – come rude awakenings and changes for the better – the United Nations and a whole host of NGOs such as Amnesty International (1961), Médecins Sans Frontières (1971) and Human Rights Watch (1978), as well as various international defence and common interest groupings.

Canto: Yes, China and Russia – that’s to say their governments – are the scary ones, simply because they can do the most damage globally, though dog knows many African, Middle Eastern and Asian thugocracies are doing terrible things today.

Jacinta: Getting more female leadership into those countries that everybody pays most attention to – such as those with the greatest destructive ability (the USA, Russia and China) – that would be absolutely key.

Canto: The three countries most fond of interfering with other countries. Funny that.

Jacinta: What’s the point of having all that power if you can’t use it to push others around? Old Drivelmouth in the USA is a perfect example. Not to mention the Taliban, etc etc etc.

Canto: So you want female empowerment so you can push blokes around?

Jacinta: Ah, touché. Yes, there’s some truth to that – after all, we’ve had millennia of being pushed around by blokes. But I don’t want to resurrect the Society for Cutting Up Men, though I must say I’m glad that manifesto was written.

Canto: We need extremists so we can feel superior to them?

Jacinta: Haha well we can just about get rid of men, once we’ve drained them of sperm. Think of black widow spiders and such. There’s a strong argument that the basis of all life is female – turning Aristotle’s views upside-down. Anyway, we’re a long way from taking over the world, unfortunately.

Canto: And such a possible world makes me think of bonobos again, where the male life isn’t too bad at all. If you accept your place.

Jacinta: Would you be happy with that?

Canto: Well, no I wouldn’t be happy to be a bonobo after my life as a human, I’d want to do all the human things – sex of course, but also exploring where we came from, what makes us tick, how the self-animating came from inanimate matter, how the universe came to be, how we can solve all the problems we create for ourselves, and enjoying all the beautiful and amazing things, like birds and bushes, music, the sea breeze, the tastes of various cheeses, a good whisky, laughs with friends and so on. As long as my female overlords allow me these joys – and I know they would – I’d be happy as a bonobo with a perpetual hard-on.

Jacinta: Haha, I’m not sure if that’s the best definition of happiness. The spicy variety is more like it. And of course you’re right, human life is potentially much more varied and complex than bonobo life. The real point is that the potential is more likely to be realised, for more people, with less macho thuggery and more female-led community. And here’s another point: hierarchy isn’t a bad thing, or rather, it’s an unavoidable thing, because we’ll never be equal in skills and knowledge, due to age, experience and upbringing. And there will always be challenges to existing hierarchies, and changes to them. It’s a matter of how we manage those changes, and females are generally better at that. As to why, that’s a good question. Maybe it’s hormonal. In any case, that’s a generalisation, which admits of exceptions.

Canto: But those hierarchies are much harder to shift in those complex communities called nations, where there are entrenched classes, such as the Party in China, or the Military in Burma, or the Theocracy in Iran, or the Billionaire CEOs in the USA. These people tend to live as far from the great unwashed as possible, often in gated communities or their equivalents, even on physically Higher Ground, as Robert Sapolsky and others have noted.

Jacinta: Yes, that’s a good point. I was thinking recently of Nixon and his crimes, and of the USA’s ludicrous and shocking Presidential pardoning system, exposed even more in recent times. Nixon was merely ‘persuaded’ to resign, and would have spent his retirement in one of those gated communities, full of backslapping commiserators, and I have few expectations of Trump experiencing anything worse. Anyway, what we need is a society, and a political system, in which this kind of scum doesn’t rise to the top in the first place. I wonder if there have ever been any brutish alpha females in the bonobo world. It’s unlikely, but there may have been the odd one-off.

Canto: You mentioned hormones. You know, I’ve never really understood what they are. I recall Sapolsky warning us against over-simplifying – assuming that testosterone is the male hormone or the aggression hormone, and that serotonin is the relaxing hormone, mostly associated with females…

Jacinta: Serotonin’s a neurotransmitter. You might be thinking of oxytocin, which is both a neurotransmitter and a hormone, apparently. Or, more likely, oestrogen?

Canto: Yes, I’ve heard of them all, but I don’t know what basket to put them in. Is a neurotransmitter a wave or a particle? Are hormones like cells, or molecules of some kind? Amino acid chains, like so much else in the body? We should do a whole self-educating conversation on that topic.

Jacinta; Absolutely. Anyway, we need more of an oxytocin-soaked society – without the downsides of drug induction, and as long as it doesn’t interfere with our sciencey rationality too much. Here’s something from a typical popular medical website about oxytocin:

Oxytocin is a hormone and a neurotransmitter that is involved in childbirth and breast-feeding. It is also associated with empathy, trust, sexual activity, and relationship-building. It is sometimes referred to as the “love hormone,” because levels of oxytocin increase during hugging and orgasm. It may also have benefits as a treatment for a number of conditions, including depression, anxiety, and intestinal problems.

Canto: Hmmm, doesn’t it just immediately make you think of bonobos? I bet they have no problems with their intestines.

Jacinta: Well it does make me fantasise about a touch of biochemical engineering, just to help the feminising process along. Whadya reckon?

Canto: Interesting. That’s for a future conversation.

References

https://www.sciencedirect.com/topics/engineering/synergistic-effect

Melvin Konner, Women after all: sex, evolution and the end of male supremacy, 2015

Robert Sapolsky, Behave: the biology of humans at our best and worst, 2018

https://my.clevelandclinic.org/health/articles/22513-neurotransmitters

https://www.medicalnewstoday.com/articles/275795

Written by stewart henderson

July 31, 2022 at 10:12 pm

bonobos, humans, sex, kids, community and work: an interminable conversation 1

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just being cosy

 

Canto: We need to face the sex issue, which is such a problematic one for humans, and far less problematic, it seems, for bonobos.

Jacinta:Yes, they don’t need a Me Too movement, coz the males are already scared of them. I mean the boss females.

Canto: Well it’s not just the males hitting on the females. In bonobo societies, it’s males on males, females on females, old on young, kids on kids, but with a minimum of fuss and bother, it seems to me. And it’s not all the time, I don’t want to exaggerate anything. There are no nymphomaniacs, whatever that means.

Jacinta: A pejorative term. The male equivalents are called studs.

Canto: Well, not always. Sometimes called sex addicts. And paedophiles of course. Suitable cases for treatment. And I remember a group calling themselves ‘sluts on bikes’, seeking to retool the term for their own benefit somehow. I think there’s a lot of confusion or uncertainty out there, about whether an overdeveloped interest in sex is good or bad. And of course there’s a big issue about sexual victims, which doesn’t seem a problem for bonobos.

Jacinta: Not a major problem, but the females appear to keep the males in line, if they go too far. After all much of the sexual stuff is just mutual masturbation.

Canto: Yeah, nowadays, human males – and maybe females – get off on porn, or their own fantasies, wanking in the safe confines of their bedrooms, imagining touchy-feelies rather than experiencing them. It’s quite sad. Bonobos don’t have that problem.

Jacinta: It’s certainly true that there are plenty of sexually unsatisfied human apes around. But maybe if they weren’t so aware of sex – especially the hypersexuality of porn – they wouldn’t be so obsessed with what they’re missing out on. Take orangutans. They’re mostly isolated, and I doubt if they spend much time masturbating…

Canto: Ah but they do spend some time on it. If the Gizmodo website is to be trusted, masturbation has been observed in at least 80 types of male primates, and 50 types of female primates, including orangutans. And I don’t quite trust that male-female disparity.

Jacinta: Yes, that’s odd. And the point is that the crotch area is the most erogenous zone for all mammals, surely – and then some. And it doesn’t require fantasising about sexy other members of your species. Think of the first time you masturbated…

Canto: I really can’t recall the first time….

Jacinta: It’s highly likely you found your pubes rubbing against something, and it felt, well, stimulating, so you rubbed some more. Nothing directly to do with sex, for us or for other mammals. When a dog starts humping your leg, it’s not actually humping, or thinking of humping, presumably.

Canto: So it’s all about chemicals, fireworks in the brain, or something? A dog humps your leg because he’s excited, and humping gets him more excited. But it’s the old chicken and egg – does it start with the humping or the excitement?

Jacinta: Well I suppose the main point for us is that masturbation is natural and common for many species, given the evolution of erogenous zones, especially the zone associated with reproduction. But I’m more interested in another phenomenon – reproduction. In spite of their interest in sex, bonobo females are unable, it seems, to produce more than a few offspring in their lives. According to Wikipedia, the most offspring produced by a human female, that we know of, is 44, 43 of whom survived infancy. That’s a woman in Uganda, whose last child was born in 2016. There are recordings of greater numbers in previous centuries, but they’re insufficiently verified. And this woman, Mariam Nabatanzi, wasn’t just showing off, she had a rare condition that caused hyperovulation. Her births included 3 sets of quadruplets, 4 of triplets and 6 of twins, and she might’ve added to the number but a procedure she underwent in 2019, at age 40, put a stop to it all.

Canto: Elon Musk would’ve been proud of her.

Jacinta: Yeah, well, I wonder if he’s helping pay Ms Nabatanzi’s food bills, though hopefully her unwonted fame would help with that. It’s interesting that both Franz de Waal and Jane Goodall mention, in the beautifully photographed Deutsche Welle documentary referenced below, that the ability of humans to reproduce rapidly compared to other primates has been a vital factor in our dominance of the biosphere, with its positive and negative impacts. De Waal suggests that this high reproductive rate is somehow due to the family structure we’ve developed, with the father helping out the mother, not so much directly as indirectly, as material provider and support. But I think this claim needs more support or more fleshing out.

Canto: Yes, it seems to fly in the face of what we know about bonobo culture, where the mother seems to be helped out by other females, and males, in a tight-knit community. Or is this an exaggeration? I recall reading that this community care, or extended family care, occurs in corvids as well. I don’t know how many chicks the average crow gives birth to in a lifetime. Anyway, it seems that the long intervals between births in chimps and bonobos is more psychological, or cultural if you like, than physiological. The mothers do much of the caring and feeding, and it’s exhausting. Humans have bottle-feeding for instance, and anyone can be in charge of that. I did it for my little brother when I was a kid, and even learned to change nappies. Human mothers are sometimes back at work weeks or even days after giving birth.

Jacinta: Which would require other carers. Maybe we’re not so selfish as we think. But then again, in the WEIRD world we’re having fewer children, and as other regions become more well-off they’re having fewer children too.

Canto: Except for Elon Musk.

Jacinta: Crows generally lay a clutch of 2-7 eggs every nesting season – that’s one clutch every year. About 40 percent of all the corvid species are co-operative breeders, a much bigger percentage than other bird species. Crows’ lifespans can vary wildly – some can live for more than twenty years, and of course it’s hard to say how many offspring they produce in a lifetime, never mind how many of their chicks survive to adulthood. But returning to humans and bonobos, both species make a habit of having sex for fun, though with bonobos it’s more of a standard thing – they don’t have killjoy religious figures or ’empowered’ celibates spoiling the party.

Canto: We’re certainly a long way from public sex. Even nudist colonies now seem a distant memory, and they were about as sexy as an old fart’s farts.

Jacinta: Well, that’s a bit rough. We’re just so much more diverse than bonobos, you can’t compare. Everything from lifetime vows of celibacy to sex dungeons, about which I know nothing.

Canto: We’ll explore them, no doubt. But of course bonobos, when they’re not eating and sleeping, have a lot of time for play. They’re not trying to create the next exciting technology or to quantise gravity or to become the richest entrepreneur in the jungle or to take over their neighbours’ territory or whatever. All play, even sexual play, and no work can be a bit mind-numbing perhaps. A bit of your old Freudian sublimation isn’t such a bad thing.

Jacinta: How about getting AI to do all the smart stuff and we just play?

Canto: Ahh, now you’re talking about the future, beyond where we’ll be, unless those longevity diets really kick in…

References

https://gizmodo.com/9-animals-that-masturbate-other-than-humans-1723592357

https://en.wikipedia.org/wiki/List_of_people_with_the_most_children

 

Written by stewart henderson

July 27, 2022 at 8:48 pm

feminism in China? Must be too busy holding up half the sky…

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Chinese feminists, happily out there, but sadly not in China

As I’ve mentioned before, it’s not just religion that’s providing a brake to the progress of female empowerment. The Chinese ‘Communist’ Party, which seems to be religiously opposed to religions of all kinds, with their popes and patriarchs, hasn’t benefitted from this opposition by promoting any of its female citizens to leadership positions.

I say ‘communist’, because  there’s surely no organisation on the planet that’s less communist than the thugocracy that currently rules China, and has done for the last seventy-odd years, since Mao bludgeoned his way to power. If we take communism to mean the dictatorship of the proletariat, clearly it will only happen when ‘prole’ and ‘dictator’ mean the same thing – that’s to say, never. And it’s a sad irony that any nation with any reference to communism in its title has always engaged in the most brutal – and very macho -authoritarianism. So basically I’ve come to consider both communism and fascism as synonymous with thugocracy.

So Mao’s statement that woman hold up half the sky was just patronising claptrap, apparently. Xi Jinping, the unutterably worthless bag of scum that is China’s latest dictator (I’m sorry, but I always get emotional where thugs like Mr Pudding and his Chinese mate – can’t think of a nickname just yet – are concerned. My anti-authoritarianism goes back to earliest childhood and is deeply ingrained), is suppressing the equality of women as part of his corruption campaign. It doesn’t seem to be phasing outspoken women in China, most of whom are destined to outlive the scumbag. Still, for the time being, they’re being muzzled, their Weibo accounts suspended, and their harassment by Party goons adds another layer to the harassment they’ve lately been experiencing on campuses and in workplaces.

These are backward steps for women in China. It was the fascinating Empress Dowager Cixi, one of China’s most under-rated political leaders, who first banned foot-binding back in 1902, a ban that was overturned, probably because it was instituted by a woman, but later reinstated. Even so, China was at the forefront of women’s rights in the early twentieth century. A researcher on women’s rights in China, Emeritus Professor Louise Edwards of the University of NSW, points out that early progress in equality and supportive legislation came from within the system rather than from grassroots activism:

If you were working in the state sector in China, as a woman in the 1950s, you had access to maternity leave, breastfeeding leave — these kinds of protections were way ahead of Australia at the time.

But the Party has become more repressive and ‘anti-western’ since the events of 1989, and especially since the rise of Mr Pingpong (okay this needs a bit of work). Clearly the Party has become more macho (there has never been a woman on the politburo standing committee, in its almost 70-year history), so feminists have had to work from outside that framework, and are more of a threat, and therefore more ‘western’. It’s all rather predictable in its stupidity. So China has dropped down the rankings for gender equality, temporarily. But Mr Pingpong will be dead meat soon enough (actually, not soon enough), and women will rise again, inevitably. The arc of the moral universe may be long, but it bends toward justice, in spite of these pingpongy, Mr Puddingy gremlins in the works. In fact, once Pingpong is out of the way, hopefully without being able to secure another fascist to replace him, feminism will likely burst into the public sphere with a vengeance, as identification with feminism is increasing big-time in China. Lu Pin, the founder of Feminist Voices, an influential media outlet shut down in 2018, remains confident about the future. An ABC article, linked below, quotes her:

Today, more young people than before agree that they are feminists. Today, the debate on feminism in Chinese society is unprecedentedly fierce.

Again, it’s a matter of nature eventually overcoming oppressive cultural artifice, but meanwhile the attitude of the Party towards increasing sexism and male brutality is to downplay the violence and to avoid at all costs any mention of feminist values and aspirations. It’s a very backward move considering that, by the 1970s, Chinese women, who in ancient China often didn’t even have their own names, formed the largest female workforce in the world. The one-child policy, introduced in 1979, led to abortions and abandonment of female infants, and a noticeable gender imbalance problem into the 21st century. Although the policy has since been relaxed, women are reluctant to become ‘baby factories’ for the Party, given the lack of support for child-rearing, and the current patriarchal fashion.

China’s first ever law dealing with domestic violence was enacted in 2016, over 40 years after Australia’s Family Law Act (1975) defined and legislated against domestic violence. However, it appears that the law is largely a well-kept secret. Frida Lindberg, in an article on women’s rights and social media for the Institute for Security and Development Policy (a Swedish NGO), writes this:

Despite the Anti-Domestic Violence Law, domestic violence cases have nevertheless continued. Some argue that the law is ineffective due to low public awareness about the issue and punishments that are too lenient. In addition, the law has been criticized for promoting family harmony and social stability, a principle that stems from Confucianism, as this seems to contradict the law’s principle of preventing domestic violence.

Lindberg’s article shines a light on current obstacles to female participation and progress in the Chinese workforce, obstacles that many WEIRD women now in their sixties and seventies (my generation) experienced regularly four or more decades ago. But of course the social media issue is new. Weibo and other social media sites became a vital outlet for women after the treatment of the so-called feminist five were muzzled, at least partially, after street protests in 2015 over domestic violence and the lack of public facilities for women. Unsurprisingly there was a backlash against feminist posts, which many in the movement saw as a good thing – any publicity being good publicity –  but the Party decided to put a stop to the argy-bargy, removing many social media accounts of prominent feminists in 2021. It also appears to be lending support to anti-feminist nationalists, who have been trolling outspoken women for anything they can find, including sympathy for Hong Kong and for oppressed minorities. The Party has used the excuse of ‘disrupting social order’ to harass and shut down whistleblowers who’ve posted about sexual harassment, but the number of views these posts garnered argues for a groundswell of concern about the issue, one way or the other. Feminists have fought back by coding their messages to avoid censorship, but this obviously has its limitations for attracting public attention, and is usually identified and reported by the ‘nationalists’.

So, it’s a ‘watch this space’ situation, or rather, watch this region. Having taught scores of Chinese women over the years, I know all about their intellect, their passion and their power. In his book Asia’s reckoning, the Australian journalist Richard McGregor described the irony of how conformist Japan has become a liberal democratic country of sorts, while the more liberal and individualist Chinese are saddled with the Party and its goons. It’s surely a temporary situation, but just how temporary is temporary?

References

https://www.abc.net.au/news/2021-06-08/feminism-in-china-internet-crackdown-erase-womens-voices/100165360

Click to access Lindberg.-2021.-Womens-Rights-in-China-and-Feminism-on-Chinese-Social-Media.-1.pdf

Richard McGregor, Asia’s reckoning, 2017

 

 

Written by stewart henderson

July 23, 2022 at 6:43 pm

Australia, religion and the appeal of eternity

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The latest Australian census figures are out, and as always I zoom in on religion and our quite rapid abandonment of….

It’s not that I’m against religion exactly, I recognise it as an attempt to understand our world, before science came along. Often to understand it as story. The story of how the world formed, and who formed it. Religions, I notice, are always about personae, doing Very Powerful things. Creating the heavens and the earth, plants and animals, and of course humans. For some kind of moral purpose, which we must constantly try to discern, from the signs and stories of the creators. And some humans are better at pinning down this purpose than others, and they become elevated as intermediaries between the creators, to whom we owe everything, and our benighted selves, tossed on the waves of godly caprice, which only seems like caprice, because the gods have a higher purpose which even the most blessed and spiritual of mortals can only partially comprehend.

Anyway, the census. According to the Australian Bureau of Statistics (ABS), ‘A question on religion has been included in all Australian censuses since 1911. Answering this question has always been optional but is answered by nearly all respondents’. In that first census, over 100 years ago, pretty close to 100% of Australians described themselves as religious – essentially meaning Christian. And things hadn’t changed that much by the 1971 census, when still a vast majority – 87 to 88 percent – described themselves as Christian, and the number of people who dared admit to any other religious belief was virtually zero. But by the seventies, the hodge-podge of regulations that made up the White Australia Policy had been dismantled, so that by this latest census (2021), religious beliefs other than Christianity were being admitted to by just over 10 percent of respondents.

But Christianity has fared particularly badly over the past fifty years, as the graph above shows. I first started paying serious attention to this trend away from Christianity after the 2006 census, and from memory, I gave a talk to the SA Humanist Society after the release of the 2011 census, noting the trend, particularly the fact that the abandonment of Christian belief was accelerating. However, I predicted, at least to myself, that this trend would soon start to ‘plateau’. My reasoning was partly based on the breakdown of Christianity into denominations. Not a complete breakdown, from my very basic research. The ABS broke it down into Catholicism, Anglicanism and Other Christian, and it was very clear that Anglicanism was fading most quickly, and Catholicism most slowly. It seemed to me that Anglicanism, which, unsurprisingly, had been the most practiced Christian religion in the early censuses, had suffered in the late twentieth and early twenty-first centuries due to its reforms and increasing liberalism (though of course it has its conservative faction). Considering that religion is supposed to be about the eternal values of the creator, unchanging since our creation, rather than about values that simply change with the times – what some call social evolution – it may have caused many Anglicans to lose faith in religion altogether, or even to switch to something more ‘eternal’, such as the Holy Roman Catholic and Apostolic Church. My prediction was that Anglicanism would continue to lose support until it bottomed out, in the fairly near future, and that Catholicism would also start to level out, what with all those cultural Catholics who built their social lives around the Church. And there was also the popularity of those Big Church evangelicals and Pentecostals, the ‘Charismatics’ that I kept hearing about.

So I was taken by surprise by the 2016 census, which saw the biggest drop in the Anglican religion of any previous census, as well as a more substantial drop in Catholicism than anticipated. The ‘other Christian’ category had also dropped, and the no religion category had risen to just over 30%. These figures upended my expectations completely, so I was more open to what the 2021 census would bring. Even so, a jump from 30% non-religious to 39% in five years is pretty amazing – but rapid change has been the norm in modern times, at least in the WEIRD world. Today we talk in terms of generations – the baby boomers, the millennials, generations X,Y and Z, and it’s all a bit hard to parse. I don’t think the generation of the 1740s would have had much difficulty in dealing with gen 1760, except of course to complain about their youthful foolishness, as Aristotle was wont to do.

So, as you can see from the graph, ‘no religion’ is pretty well certain to replace Christianity as the largest religious category in the next census, while owing to our increasingly multicultural mix, other religions will continue to rise, though not substantially. Interestingly the largest jump in religious presence since the 2016 census is that of the Yazidis, a largely Kurdish-speaking religious group from northern Iraq and surrounding regions, fleeing from persecution by the so-called Islamic State. Though it only ‘took off’ in the 12th century, its origins are apparently pre-Islamic and pre-Zoroastrian, later tinged with Sufi and Islamic influences. So, I learn something new every day.

Of course, the cultural make-up of Australia is changing, but slowly. We could do with expanding our immigration program, and behaving in a less hostile and cruel way towards refugees. I’m not religious of course, but bringing into the country a wider variety of religio-cultural groups might tend to water down the influence of the very male Judeo-Christian god that has been worshipped in this country for so long. Even if these new religions have their own patriarchal features, as most do, the divisions between them might tend to dilute the patriarchy of Catholicism, the Christian religion that has always most concerned me. Catholicism began to challenge Anglicanism as the most practiced, or at least believed in, denomination in Australia in the post-war period, though there was always a large Catholic presence, particularly Irish-Catholic, before that. It continues to be the most persistent denomination, but it will clearly never be the politically dominant influence it was in the 1950s. Even so, it’s noticeable that the religiosity of our political leaders, our parliamentarians, in terms of numbers, is greater than the general population – just as the average age of parliamentarians is greater than the general population.

As mentioned, the above graph clearly shows that the biggest religious category in the next census will be ‘no religion’. And that category will continue to grow over the next decades, and even the immigrants with their different religious varieties may go the way of the majority.

But us oldies may not, or will not be here to witness what happens. What will these developments mean for the nation? How will it have changed our politico-social landscape after we have passed? That’s the sad thing, life is very addictive, and we don’t want it to stop. We always want to know what happens. No wonder eternal life is so profoundly appealing.

 

Written by stewart henderson

July 16, 2022 at 10:46 pm

What is a heat pump?

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from How Stuff Works

Canto: So We’ve been reading, inter alia, Saul Griffith’s practical and informative little renewable energy tome, The big switch, in which he mentions, inter alia, heat pumps and their relative efficiency. He may have explained heat pumps somewhere, but I was adrift at the time. Can you inform me?

Jacinta: Well, instead of rifling through the book, which unfortunately doesn’t have an index, let’s google it. Australia’s largest electricity generator has a piece boosting heat pumps, which may sound biased, but Griffith boosts heat pumps too, so I’m presuming it can be trusted. The humble heat pump, as it’s described, isn’t a new technology, and is a proven winner in terms of energy efficiency, for example in reverse-cycle air-conditioning. Particularly so for heating. It ‘gathers heat from outside and warms it to a higher temperature, then moves it from one place to another’.

Canto: It gathers heat from outside. Easier said than done, surely. Presumably it sucks?

Jacinta: Well apparently there’s more than one type of heat pump technology, and this article mentions two – air sourced, and ground sourced (geothermal). And as they point out, it may seem counter-intuitive to think you can extract heat from outside, whether from the air or from under the ground, in the depths of winter. But heat is energy, and even in the winter there’s a lot of that energy around. Anything above absolute zero contains energy, and there’s surprisingly little difference between winter and summer heat energy.

Canto: Well I notice they highlight this statement about your standard heat pump:

It uses a compressor and liquid or gas refrigerant (the stuff that’s in your fridge) – a substance that absorbs heat from the environment – to concentrate heat and move it around to warm your house.

Now that’s something that needs explaining.

Jacinta: Well, off-hand, I understand that heat tends to disperse, when it can, from a compressed high-energy state to a low-energy one, something to do with a law of thermodynamics…

Canto: I suppose heat pumps come under the umbrella of HVAC systems – heating, ventilation and air-conditioning. But do all air-conditioning systems work with heat pumps?

Jacinta: Well I don’t think so – there’s evaporative air-conditioning, which I think’s quite different.

Canto: So a heat pump just is a reverse-cycle aircon? How, exactly, does it do the cooling? Or the heating for that matter.

Jacinta: Just off the top of my head, the cooling works just as the heating does, but in reverse. It sucks the hot air from the room and chucks it outside. And then, uhhh, brings colder air in somehow, or cools it in that big box, somehow like a refrigerator…

Canto: Brilliant. So now I’m reading How Stuff Works on heat pumps. And of course you’re on the right track, it’s all about heat transfer, so it doesn’t require energy for burning..

Jacinta: Or freezing?

Canto: Uhhh, it requires energy, of course, but it’s pretty energy-efficient. They’re particularly good in moderate climates like ours (In Adelaide), because you don’t have to transfer large amounts of heat from outside or inside to make life comfortable.

Jacinta: It’s pulling and pumping. You pull heat from the outside, or inside depending on the season, and pump  it into the inside, or outside.

Canto: Yeah, I get that, but what’s the mechanism?

Jacinta; Well, sucking air in is pretty simple, our mouths do it all the time, and think of a vacuum cleaner, which does it more powerfully, but generally for shorter periods. Aircons just require a gentle, longer-term suck.

Canto: Very technical.

Jacinta: That’s probably why the emphasis is on the pumping. Now, I’m talking about air-source heat pumps in particular, because that’s what we have in our home – on the wall, with another box outside. What they call a split system. So, I’m going to quote at some length from How Stuff Works, and then we’ll try to break it down, if necessary:

One of the most common types of heat pumps is the air-source heat pump. These take heat from the air outside your home and pump it inside through refrigerant-filled coils, not too different from what’s on the back of your fridge. The air source variety is pretty basic, and you’ll find two fans, the refrigerator coils, a reversing valve and a compressor inside to make it work.

The key to allowing the air-source heat pump to also cool is the reversing valve. This versatile part changes the flow of the refrigerant so the system can operate in the opposite direction. So instead of pumping heat inside your home, the heat pump releases it, just like your air conditioner does. When the refrigerant is reversed, it absorbs heat on the indoor side of the unit and flows to the outside. It’s here that the heat is released, allowing the refrigerant to cool down again and flow back inside to pick up more heat. This process repeats itself until you’re nice and cool.

Canto: Hmmm, that sort of makes sense, the hot air inside is made to flow through these ‘refrigerant filled coils’, but what exactly is this refrigerant? Didn’t they use to use freon or something, which damaged the ozone layer? And this doesn’t exactly sound like a split system. It sounds more like an all-in-one.

Jacinta: Yeah so not all reverse cycle aircons are split systems. Apparently split systems are easy to install and work pretty efficiently. I can’t easily find how they compare with all-in-ones but I suspect they’re pretty similar, efficiency-wise. Another type of reverse cycle aircon is ducted., which can warm or cool several rooms at once through various ducts. The refrigerant most used nowadays is puron, a HFC (hydrofluorocarbon) known to be non-damaging to the ozone layer. It’s become the standard refrigerant since 2015, but our aircon is surely older than that. Freon, the culprit you mentioned, hasn’t been used in new air-conditioning systems, at least in the USA, since 2010. Freon is a HCFC (hydrochlorofluorocarbon), apparently much naughtier than HFCs. Of course, I’ve no idea what our system uses.

Canto: Okay, last question. I don’t think we’ve answered how the pump thing works.

Jacinta: Well I suppose it does so just as mysteriously and simply as it sucks. We suck air in with our mouths and noses – or we suck in oxygen, and how we separate that gas from all the others is another story – and we pump out carbon dioxide. All without the slightest effort, apparently.

Canto: So we’re actually heat pumps? And we’re pumping out CO2 at an alarming rate, eight billion of us. We’re the principal cause of global warming!

Jacinta: Haha, I think you’ll find it’s a bit more complex…

Written by stewart henderson

July 13, 2022 at 8:23 pm

the shipping industry – a bit of a global warming headache

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Ok, that’s sulphur oxides, nitrogen oxides, carbon dioxide, particulate matter and non-methane volatile organic compounds

I’ve been alerted, by a brief piece on a New Scientist podcast, and then by some passages in Tim Smedley’s book Clearing the air: the beginning and end of air pollution, about some pretty disturbing stats on the polluting and greenhouse impact of the world’s shipping industry – a factor we don’t often consider when we attempt to reduce our personal environmental impact. We tend to focus on the products we consume, the cars we drive, the homes we heat, the plane trips we take and so forth. But once it’s pointed out to us it becomes obvious. We’re the recipients of a vast global trading network involving foodstuffs, appliances and gadgetry of all sorts, as well as bulk supplies of crude oil, iron ore and a host of other raw materials, brought to us by more or less massive marine vessels.According to an article in Chemical & Engineering News (C&EN), goods weighing 11 billion tonnes were shipped across our oceans in 2019, a 3-billion tonne increase from a decade before. And the increase is expected to … increase. So how are these vessels powered? To quote from the C&EN article,

“The shipping industry uses more than 300 million tons of fossil fuels every year, roughly 5% of global oil production,” says Camille Bourgeon, a specialist in air pollution and energy efficiency in the marine environment at the IMO [the International Maritime Organisation – an agency of the UN]. In 2018, global shipping activity emitted roughly 1.05 billion t of carbon dioxide into the atmosphere, accounting for about 2.9% of the total global anthropogenic CO2 emissions for that year, according to the IMO’s 2020 greenhouse gas study.

What’s worse is that for decades the shipping industry has been using the lowest grade, most noxious fuels, ‘the stuff no-one else wants’, as one maritime engineer describes it. This ‘residual fuel’ is also called HFO, for ‘heavy fuel oil’, which the oil industry has been more than happy to provide to the shipping industry rather than having to get rid of it some other, more expensive way. And when you’re out in the middle of the ocean, who’s going to check your emissions? The fuel used has seriously high sulphur content, and once ships come into port, the cargo is offloaded onto diesel trucks and then often onto diesel locomotives. Here are some of Tim Smedley’s opening remarks on the industry:

[Shipping] is easily the transport sector with the worst history. Shipping emissions contribute nearly 15% of NOx [nitrogen oxides including nitric oxide and nitrogen dioxide, some of the worst air pollutants] and 13% of sulphur dioxide emissions globally, and these numbers are increasing. Due to growing populations and consumer spending, more and more supertankers set sail every year. Since 1985 global container shipping has increased by about 10% annually, with only brief dips for each recession.

There seems to be no stopping this growth, and about a quarter of this transport is fuelled by crude oil. As Smedley points out, this ‘gives us the headache-inducing fact that a quarter of all shipping emissions come from shipping the fuel needed to produce the emissions’.

As mentioned, sulphur dioxide is a major constituent of HFO. On the website of Aeroqual, a company that provides air monitoring systems, I found this disturbing claim – the sulphur dioxide of HFO is 2700 times higher than that of road fuel. Sulphur dioxide emissions have been dropping for years in developed countries – a 76% decrease in Europe between 1990 and 2009 – leaving shipping as the primary source.

As also mentioned, ports are some of the most atmospherically noxious places on the planet. Most of them use diesel-powered machinery for off-loading and transportation. Diesel emissions significantly increase cancer risks according to a host of epidemiological studies, and various engine improvements have barely kept up with improvements in emissions monitoring, which have highlighted further dangers. But the diesel issue probably requires a whole new post.

The shipping industry, setting aside all those smelly and sick-making ports, and the sulphur dioxide problem, is a major contributor to greenhouse emissions, releasing over 3% of our carbon dioxide, a percentage that is set to rise in the aftermath of the covid pandemic. A website called ship technology sets out a plan to address the issues, which reminds me of the plans regularly emanating from the IPCC, requiring targets which seem to be seldom met by the major emissions culprits. The plan includes improved ship-to shore data feed technology, exhaust emission technology, behavioural change such as slow steaming (yes, that just means slowing down) and more preventive maintenance, and alternative fuels such as LNG, hydrogen and even solar. LNG is the most touted alternative fuel due to requiring fewer alterations to shipping infrastructure, though it’s surely an interim solution.

The IMO has been rather defensive about its role as the shipping regulator, and the degree of progress made in reducing emissions. Certainly it’s a difficult industry to police, with many nations and companies involved, including military vessels worldwide, which have other priorities, to put it mildly. But it’s clear that shipping officials are feeling the pressure. As one of them put it:

“… can shipping reduce more greenhouse gas emissions? I’m sure it will. But it’s difficult to say how much particularly not knowing the consequences from regional regulations. There seems to be a wish to require unrealistic emission reductions in order to collect money from ships.”

These remarks make me wonder whether money is being collected from land-based greenhouse emitters, and if not, why not? Interestingly, the same official has this to say in the industry’s defence:

“When discussing short-term measures, the figure over the next 10 years will bring the shipping carbon intensity reduction in 2030 to more than 40%, below the year 2008. This is a remarkable achievement by a sector that is, and will remain, the most efficient mode of transportation”.

This appears to be saying that the most efficient form of transport in the shipping sector is, and always will be, shipping. Or maybe I’m reading it wrong. In any case, they’re on the case, which is great. Must remember to have another look in 2030.

References

https://cen.acs.org/environment/greenhouse-gases/shipping-industry-looks-green-fuels/100/i8

Tim Smedley, Clearing the air: the beginning and the end of air pollution, 2019

https://www.aeroqual.com/blog/ship-pollution-port-air-quality

https://en.wikipedia.org/wiki/Diesel_exhaust

https://www.ship-technology.com/analysis/guidelines-and-goals-reducing-shippings-emissions/

 

 

Written by stewart henderson

July 10, 2022 at 1:29 pm

exploring spermatogenesis

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Canto: So If Charles Darwin was alive today, he’d be gobsmacked at the facts derived from the ‘random variation’ end of his theory of natural selection from random variation. I’m talking about genes, DNA, genetic recombination and all that we know about meiosis and mitosis, spermatogenesis and oogenesis, genomics and epigenetics, mitochondrial DNA, ribosomes, mRNA, proteins and the like, none of which I’m particularly knowledgeable about – but surely even what I know about it all would make Darwin’s head explode.

Jacinta: Yes, and of course Darwin did all his studies on phenotypes, a term he would never have heard. He studied pigeons, finches, barnacles, fossils and a wide variety of plants. But he was never able to ‘crack the code’ of random variation. Why did offspring differ from parents? Why did those offspring vary from the utterly dysfunctional to the super-functional? For a time he considered pangenesis, his coinage, as a solution. This involved ‘gemmules’ inherited from both parents, blended together and somehow modified by the environment, presumably in a Lamarckian way. So Darwin never quite cracked the code of inheritance as we understand it today, but the work with plants which occupied his last years – allowing him to avoid the acrimony around human origins surrounding the publication of On the origin of species – produced important results for the understanding of plant reproductive biology. Take this quote from the Smithsonian magazine:

Darwin designed highly rigorous experiments and made predictions—which turned out to be correct—using his theory of natural selection. For example, he predicted that the myriad floral adaptations he saw existed to ensure that flowers were outcrossed, or fertilized by individuals other than themselves. He then tested this hypothesis with over a decade of pollination experiments and found that self-pollination leads to lower fitness and higher sterility. Inbred plants, like inbred animals, don’t fare well, at least over time—a phenomenon that’s now known as inbreeding depression.

Canto: Right, but let’s not get bogged down in the history of reproductive biology and the birth of genetics here, as it’s hard enough for me to comprehend meiosis and mitosis, gametes and zygotes and all the rest, as we understand it all today. We’ve previously written about meiosis, but I want to understand, or to begin to understand, in this post, how the process of producing gametes is so different in male and female mammals.

Jacinta: Okay, so we’re talking about gametogenesis. The male gametes are called sperm, the female gametes are called eggs, and so have two forms of gametogenesis, spermatogenesis and oogenesis. In this post I’ll focus on the male, saving the best for another post. So sperm is formed in the testes…

Canto: The ballsacks?

Jacinta: Uhh, well, the sack is just the sack, also known as the scrotum. Inside, you’ll find a testicle, hopefully. And as you well know there are, ideally, two of them. That is, two sacks, each with its testicle. And a testicle is about as complex as any other piece of biological machinery – a lifetime’s learning worth. Take this illustration, courtesy of ken hub.com:

Note the seminiferous tubules above. That’s where the sperm is formed, first by the mitotic division of a spermatogonial stem cell…

Canto: Eh what? How did they get in there?

Jacinta: Okay let me try to understand this for myself, but I may get more and more bogged down. It all begins at the beginning, during the early stages of male foetal development. The primordial germ cells differentiate in the testis, in these seminiferous tubules… But let me first fast forward to the end of the process and describe a complete, mature sperm cell or spermatozoon. That’s an active, motile sperm – plural spermatozoa, or just plain sperm. It’s divided into three parts, essentially, the head, the midpiece and the tail. At the head we find the acrosome and the tightly packed nucleus. The midpiece contains the mitochondria. which provides energy for the sperm’s motility, and the tail is essentially the flagellum, the sperm’s outboard motor, so to speak.

Canto: Okay, so that’s the end product – get back to the spermatogonial stem cells and the seminiferous tubules.

Jacinta: Fine. Spermatogonia are undifferentiated male germ cells, or sperm cells. It’s hard to find a simplified, but not overly simplified, explanation of how pluripotent or totipotent stem cells become germ cells, or any other cells for that matter, but it begins in the embryo. A cell signalling process in the embryo induces a small, transient proportion of the cell mass, the primitive streak, to become primordial germ cells (PGCs), along with other cells. This process is called gastrulation, in which the embryo begins to differentiate into distinct cell lineages. For the PGCs, according to a paper cited in Wikipedia, ‘The specification of primordial germ cells in mammals is mainly attributed to the downstream functions of two signaling pathways; the BMP signaling pathway and the canonical Wnt/β-catenin pathway’. This is essentially about regulatory proteins, I think.

Canto: This is getting too complicated for me. How come that second pathway is canonical?

Jacinta: See, you are paying attention. That Wnt/beta-catenin pathway gets a lot of attention in scientific papers, because we know that its deregulation is a problem in serious diseases and cancers. Basically these pathways are essential for embryonic development. The terms ‘canonical’ and ‘noncanonical’ are terms of art used to describe the standard production of Wnt proteins for development or homeostasis, and less well-known, or later-discovered pathways. I think. Anyway, let’s get back to spermatogonia, of which there are three types – A dark, A pale and B. The A dark spermatogonia are the reserves, and they don’t generally go through the mitosis process – they remain dormant. The A pale cells (so called because they have pale nuclei compared to the A dark cells) undergo mitosis to become the type B cells, which grow and develop to become primary spermatocytes, a process called spermatocytogenesis, truly. All of this occurs, as mentioned, in the seminiferous tubules of the testes, and begins at puberty.

Canto: Okay so how do these primary spermatocytes differ from spermatozoa, or how do they become spermatozoa?

Jacinta: The primary spermatocytes are diploid cells, so they need to undergo meiosis to become gametes. After meiosis 1, two haploid cells are formed, called secondary spermatocytes. And of course, being diploid cells undergoing that first process of meiosis, there’s this crossing over or recombination that occurs, shuffling the deck so to speak. And this is followed by meiosis 2, replicating the haploid cells, and so forth. But you ask how the spermatozoa are formed as an end product, so I need to take us back to those tubules in the testes. They’re packed with particular cells called Sertoli cells, and just outside the tubules are Leydig cells, which produce testosterone. Anyway, once these sperm cells have developed further they travel up to the epididymis via the rete testis, where they continue to mature, ready for ejaculation. They reach the rete testis, and presumably also the epididymis, by means of peristalsis, which you’ll know about from the intestines and other parts of the body.

Canto: Sort of. You think you know about stuff until you find out what you don’t know, which is overwhelmingly vast. Mais, continue..

Jacinta: So the last transformations, making them those mobile little tadpole-like critters, occur in the epididymis. But returning to those tubules. There are lots of Sertoli cells in there, and the sperm is developed in the gaps between them, strangely enough, but they acquire nutrients from those cells to help them along. Their journey between the cells takes them from the outer membrane of the tubule to the lumen. At the beginning of this journey they’re called spermatogonia. They’re going to go through this differentiating process to finally become spermatozoa. Now I’ve already partially described the first step, when a spermatogonium divides by mitosis, into two cells, one of which is kept in reserve, the Ad or ‘dark’ cell. The Ap or ‘pale’ cells continue on the pathway between the Sertoli cells towards the lumen, somehow becoming B cells – don’t know how that happens, but it involves mitosis, perhaps with nutrients from the Sertoli cells. I think, because the process of mitosis is continuous, those reserve cells are left behind all along the pathway. Or maybe not. But that pathway is obstructed along the way by ‘tight junctions’ between the Sertoli cells, which create separate compartments as they open and close before and behind the sperm cells (which are now called primary spermatocytes) like locks in a canal. Now these compartments, called basal and lumenal compartments, aren’t empty, they’re full of chemicals, signalling proteins and such, a different mix for each compartment, which add to the spermatocyte’s development. So the sperm grows as it travels along this pathway, accumulating more cytoplasm. And the junctions close very tightly after the sperm moves through, to prevent leakage into the next chemical environment. Now, somewhere along this pathway between the Sertoli cells, the primary spermatocyte is ready to divide into two secondary spermatocytes via meiosis, a very different form of cell division from mitosis.

Canto: Yes, meiosis has those two parts, ending with four haploid cells from one diploid cell, and genetic recombination to make us all unique.

Jacinta; Okay, moving right along, so to speak, those four haploid cells are now called spermatids, and they continue to mature in the lumen. They’re still not motile, they’re rounded cells at first, but they go through lots of changes, to the conformation of the DNA, for example, with histone proteins being replaced by protamines. We’re now entering the final processes, known as spermiogenesis, which I think occurs after transportation to the epididymis. The cytoplasm is removed, the acrosomal cap is formed, and the other structures I mentioned at the outset, the mitochondrial spiral and the fibres that form the flagellum, all take shape. This whole process, from spermatogonia to spermatozoa, takes about 65 days.

Canto: Okay, that’s enough of all that, I don’t particularly want to learn about seminal fluids and ejaculation at this point, fascinating though that might be – I’m more interested in the female stuff, the generation of eggs, known as oogenesis.

Jacinta: So that for you to detail in a future post.

References

https://embryo.asu.edu/pages/charles-darwins-theory-pangenesis

https://www.smithsonianmag.com/science-nature/charles-darwin-botanist-orchid-flowers-validate-natural-selection-180971472/

https://sciencing.com/difference-female-mammals-male-mammals-8092368.html

Spermatogenesis | Reproductive system physiology | NCLEX-RN | Khan Academy (video)

https://en.wikipedia.org/wiki/Germline_development#Germ_line_development_in_mammals

https://www.biologyonline.com/dictionary/spermatid

Written by stewart henderson

June 28, 2022 at 3:21 pm

still bitten by the bonobo bug…

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Having written quite a few essays on a future bonoboesque world, I’ve found myself in possession of a whole book on our Pan paniscus relatives for the first time. All that I’ve gleaned about these fellow apes until now has been from the vasty depths of the internet, a gift that will doubtless keep on giving. My benefactor apologised for her gift to me, describing it as a coffee-table book, perhaps more pictorial than informative, but I’ve already learned much that’s new to me from the first few pages. For example, I knew from my basic research that bonobos were first identified as a distinct species in the late 1920s or early 1930s –  I could never get the date straight, perhaps because I’d read conflicting accounts. De Waal presents a more comprehensive and interesting story, which involves, among other things, an ape called Mafuka, the most popular resident, or inmate, of Amsterdam Zoo between 2011 and 2016, later identified as a bonobo. The zoo now features a statue of Mafuka.

More important, though, for me, is that everything I’ve read so far reminds me of the purpose of my bonobo essays, but also makes me wonder if I haven’t focussed enough on one central feature of bonobo society, probably out of timidity. Here’s how De Waal puts it:

It is impossible to understand the social life of this ape without attention to its sex life: the two are inseparable. Whereas in most other species, sexual behaviour is a fairly distinct category, in the bonobo it has become an integral of social relationships, and not just between males and females. Bonobos engage in sex in virtually every partner combination: male-male, male-female, female-female, male-juvenile, female-juvenile, and so on. The frequency of sexual contact is also higher than among most other primates.

In our own society, definitely still male-dominated but also with a legacy of religious sexual conservatism, this kind of all-in, semi-masturbatory sexual contact is absolutely beyond the pale. I’m reminded of the Freudian concept of sublimation I learned about as a teen – the eros or sex drive is channelled into other passionate, creative activities, and, voila, human civilisation! And yet, we’re still obsessed with sex, which we’re expected to transmute into sexual fulfilment with a lifelong partner. Meanwhile, the popularity of porn, or what I prefer to call the sex video industry, as well as the world’s oldest profession, indicates that there’s much that’s not quite right about our sex lives.

This raises questions about monogamy, the nuclear family, and even the human concept of love. This is ancient, but nevertheless dangerous territory, so for now I’ll stick with bonobos. As with chimps, female bonobos often, though not always, move to other groups at sexual maturity, a practice known as philopatry. Interestingly, this practice has similarities to exogamous marriage practices, for example among some Australian Aboriginal groups. It’s interesting, then, that female-female bonds tend to be the strongest among bonobos, considering that there’s no kinship involved.

Needless to say, bonobos don’t live in nuclear families, and child-care is a more flexible arrangement than amongst humans, though the mother is naturally the principal carer. And it seems that bonobo mothers have a subtly closer relationship with their sons than their daughters:

the bond between mother and son is of particular significance in bonobo society where the son will maintain his connection with his mother for life and depend upon her for his social standing within the group. For example, the son of the society’s dominant female, the strong matriarch who maintains social order, will rise in the ranks of the group, presumably to ensure the establishment and perpetuation of unaggressive, non-competitive, cooperative male characteristics, both learnt and genetic, within the group.

Considering this point, it would be interesting to research mother-son relations among human single-parent families in the WEIRD world, a situation that has become more common in recent decades. Could it be that, given other support networks, rather than the disadvantages often associated with one-parent families in human societies, males from such backgrounds are of the type that command more respect than other males? Particularly, I would suspect, from females. Of course, it’s hard to generalise about human upbringing, but we might be able to derive lessons from bonobo methods. Bonobo mothers rarely behave punitively towards their sons, and those sons remain attached to their mothers throughout their lives. The sons of high-status females also attain high status within the male hierarchy.

Yet we are far from being able to emulate bonobo matriarchy, as we’re still a very patriarchal society. Research indicates that many women are still attracted to high-status, philandering men. That’s to say, they’ve been ‘trained’ to climb the success ladder through marriage or co-habitation than through personal achievement. They’ve also been trained into the idea of high-status males as dominating other males as well as females. It is of course changing, though too slowly, and with too many backward moves for the more impatient among us. Two macho thugocracies, Russia and China, are currently threatening the movement towards collaboration and inclusivity that we see in female-led democracies such as Taiwan, New Zealand and a number of Scandinavian countries. It may well be that in the aftermath of the massive destruction wrought by these thugocracies, there will come a reckoning, as occurred after the two ‘world wars’ with the creation of the UN and the growth of the human rights movement and international aid organisations, but it is frustrating to contemplate the suffering endured in the meantime, by those unlucky enough to be born in the wrong place at the wrong time.

Now of course all this might be seen as presenting a romanticised picture of bonobos (not to mention female humans), which De Waal and other experts warn us against. The difference in aggression between bonobos and chimps is more a matter of degree than of type, perhaps, and these differences can vary with habitat and the availability of resources. And yet we know from our studies of human societies that male-dominated societies are more violent. And male domination has nothing to do with simple numbers, it is rather about how a society is structured, and how that structure is reinforced. For example I’ve written recently about how the decidedly male god of the Abrahamic religions, originally written as YWH or Elohim, emerged from a patriarchal, polygamous society in the Sinai region, with its stories of Jacob and Abraham and their many wives, which was reinforced in its structure by origin myths in which woman was created out of a man’s rib and was principally responsible for the banishment from paradise. The WEIRD world is struggling to disentangle itself from these myths and attitudes, and modern science is its best tool for doing so.

One of the most interesting findings, then, from modern neurology, is that while there are no categorical differences between the male and the female brain in humans, there are significant statistical differences – which might make for a difference in human society as a whole. To explain further: no categorical difference means that, if you were a professional neurologist who had been studying the human brain for decades, and were presented with a completely disembodied but still functional human brain to analyse, you wouldn’t be able to assert categorically that this brain belonged to a male or a female. That’s because the differences among female brains, and among male brains, are substantial – a good reason for promoting gender fluidity. However, statistically, there are also substantial differences between male and female brains, with males having more ‘grey’ material (the neurons) and females having more ‘white’ material (the myelinated connections between neurons), and with males having slightly higher brain volume, in accord with general sexual dimorphism. In a 2017 British study involving some 5,000 subjects, researchers found that:

Adjusting for age, on average… women tended to have significantly thicker cortices than men. Thicker cortices have been associated with higher scores on a variety of cognitive and general intelligence tests.

This sounds promising, but it’s doubtful that anything too insightful can be made of it, any more than a study of bonobo neurophysiology would provide us with insights into their culture. But, you never know…

References

Frans De Waal & Frans Lanting, Bonobo: the forgotten ape, 1997.

https://www.humancondition.com/freedom-the-importance-of-nurturing-in-bonobo-society/

https://www.science.org/content/article/study-finds-some-significant-differences-brains-men-and-women

on the origin of the god called God, part 2: the first writings, the curse on women, the jealous god

Written by stewart henderson

June 13, 2022 at 2:43 pm

exploring meiosis

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Canto: So I’m trying to get my head around meiosis in general, and how the parental chromosomes get assorted in the process. I understand that Mendel arrived at his law or principle of independent assortment by noting the resultant phenotypes from particular crosses, especially dihybrid crosses. He knew nothing about gametes and meiosis, an understanding of which didn’t get underway until a decade or more after his 1865 experiments…

Jacinta: Well, meiosis is a v v amazing process that deserves lots of attention, because if not for, etc….

Canto: But what is meiosis for, I don’t even understand that.

Jacinta: It’s for the production of gametes – the sperm and egg cells in mammals. And that’s interesting, because, according to Medical News Today, ‘Females are born with all the eggs they will ever have in their lifetime. The amount decreases until a person stops ovulating and reaches menopause’. According to a graph they present, the number of egg cells produced is at its peak long before birth, and has reduced about tenfold by the time of birth, to about one or two million. This number continues to reduce through life, though it remains relatively stable during the period of ‘optimum fertility’ from about ages 18 to 31, when the number of eggs is around 200,000, with a lot of individual variation.

Canto: So, meiosis occurs entirely while the infant is in the womb? For females at least. And what exactly is ovulation?

Jacinta: Yes, egg cells don’t regenerate like other cells. Remember, tens of billions of our somatic cells die every day, and are being replaced – mostly. As to ovulation, this occurs as part of the menstrual cycle, which occurs with females at puberty. During menstruation, mature eggs are released from the ovaries, which are on the left and right sides of the uterus and connected to it by the fallopian tubes.

Canto: What do you mean by mature eggs? Aren’t they always mature?

Jacinta: Hmmm. Detour after detour. Four phases are recognised in the menstrual cycle – menstruation, the follicular phase, ovulation and the luteal phase. It’s the follicular phase that produces mature eggs, through the release of follicle stimulating hormone (FSH) by the pituitary gland. Do you want me to go into detail?

Canto: No, let’s get back to meiosis – but I always knew there was something fshy about the menstrual cycle. So meiosis is about haploid cells producing more haploid cells? You mentioned that egg cells, which are haploid cells, are at their peak long before the birth of a female child, a peak of around 10 million. But where does the first haploid cell come from, when a child starts as one fertilised egg – a diploid cell? Haploid cells combining to form diploid cells is one amazing process, but diploid cells separating to form haploid cells?

Jacinta: Okay so here’s what I think is happening. A human being starts as a diploid cell, a fertilised egg. As cells differentiate, which happens quite early, some become germ cells. But they’re diploid cells, like all the others, not haploid cells. So meiosis starts with diploid cells.

Canto: Okay, so what differentiates a germ cell from other somatic diploid cells?

Jacinta: I don’t know, just as I don’t know what makes a pluripotent or totipotent cell become a brain cell or a blood cell or whatever. This presumably has a lot to do with genetics, epigenetics and the production of endless varieties of proteins that make stuff, including germ cells. Which presumably are not egg cells or sperm cells, which are haploid cells, or gametes. And these germ cells can undergo mitosis, to reproduce themselves, or meiosis, to produce gametes. So now, at last, we describe the process, and much of this comes from Khan Academy. There are two ’rounds’ of meiosis – M1 and M2 – each of which has a number of phases. In M1 the diploid cell is split into two haploid cells each with 23 chromosomes, and in M2 the haploid cells reproduce as haploid cells, so that at the end of the cycle you have four haploid cells. And in each of these ’rounds’ there are the four phases, prophase, metaphase, anaphase and telophase. PMAT is how to remember it. And then there’s interphase, where cells just going on being themselves and doing whatever they do – though it’s important to know what happens during interphase for these other stages.

Canto: The complexity of it all is fairly mind blowing. Molecules that have a code for making proteins that perform all these functions that produce a huge variety of cells every one of which – apart from the gametes – has a nucleus containing 23 chromosomes from your mother and 23 from your father. Trillions of them!

Jacinta: Yes, it’s certainly amazing – and billions of those cells die and are replaced every day. And not just in humans but in dogs and bonobos and cetaceans and whatnot.

Canto: But here’s a thing – we’re talking about gametes, also known as germ cells, which may be female or male – sperm cells or egg cells. But sperm are also known as spermatazoa, and they’re much tinier and less complex than egg cells, and also far more numerous. Is a spermatozoon a sperm cell, or do lots of spermatozoa live in one cell, or what? One ejaculation releases – how many of these tiddlers?

Jacinta: Well sperm counts can range from about 15 million or less per millilitre of semen (that’s a low sperm count) to somewhere between 200 and 300 million. An ejaculation can vary in volume of course – generally about a teaspoon, which might be as much as 5mls. And, yes, a single sperm or spermatozoon is a male gamete, much smaller than the female ovum. So, yes, male sperm, like male political leaders, make up in numbers for what they lack in complexity.

Canto: Okay so let’s get started with PMAT and all that.

Jacinta: Well it’s all very miraculous or mind-blowing as Salman Khan rightly emphasises – to think that this complexity comes from mindless molecules and all. But here goes, and it cannot help but be a simplified description. So we start with a germ cell – and I’m not sure how this particular type of diploid cell is distinguished from other diploid cells…

Canto: Or whether, even though it’s called a germ cell, it is essentially different in male bodies as compared to female bodies, since they produce such different gametes…

Jacinta: Yeah well I’ll keep that in mind as we progress. Now we start with the interphase, during which time the chromosomes in the nucleus are synthesised. Interphase is generally subdivided into three phases, Gap 1 (G1), Synthesis (S) and Gap 2 (G2). The cell itself experiences a lot of growth during interphase.

Canto: Too vague.

Jacinta: Well I’m just getting started, but I’m not writing a book here.

Canto: Are you going to explain how the chromosomes are ‘synthesised’?

Jacinta: Probably not, this is just a summary.

Canto: I want to know about chromosome synthesis.

Jacinta: Sigh. You’re right, it sounds pretty important doesn’t it. So let’s focus in detail on interphase, which I think is much the same whether we’re looking at mitosis or meiosis.  If you consider a whole cell cycle, from its ‘birth’ – usually through mitosis – to its ‘death’ (through mitosis again? I’m not sure), 95% of its time is spent in interphase, during which it doubles in size. It is, in a sense, preparing itself for chromosomal replication and cell division. Here’s a quote from a text book, Concepts of Biology, which I found online, describing the first stage of interphase:

The first stage of interphase is called the G1 phase, or first gap, because little change is visible. However, during the G1 stage, the cell is quite active at the biochemical level. The cell is accumulating the building blocks of chromosomal DNA and the associated proteins, as well as accumulating enough energy reserves to complete the task of replicating each chromosome in the nucleus.

Canto: So it’s a clever cell, actively accumulating the material to build and replicate its particular and unique DNA – I mean unique to the particular soma that it somatically serves, along with several trillion others.

Jacinta: Actually, another source tells that the G stands for growth, which I think makes more sense. The next stage is the S or synthesis phase. Now at this stage, or the beginning of it, the chromosomes exist largely as chromatin, a kind of mixture of DNA and proteins. Histones, in particular are important proteins for packaging the DNA into a tight enough space to fit in the nucleus. I mean, 23 pairs of chromosomes doesn’t really tell you how much DNA and other molecules it all amounts to. Now, this S phase is really complicated, and summaries don’t do it justice. Here’s a quote from yet another source to kick things off:

The S phase of a cell cycle occurs during interphase, before mitosis or meiosis, and is responsible for the synthesis or replication of DNA. In this way, the genetic material of a cell is doubled before it enters mitosis or meiosis, allowing there to be enough DNA to be split into daughter cells. The S phase only begins when the cell has passed the G1 checkpoint and has grown enough to contain double the DNA. S phase is halted by a protein called p16 until this happens.

So you’re asking how these chromosomes are synthesised. Note how this says ‘synthesis or replication’, so it’s presumably about the same sort of process that occurs when cells and their chromosomes are replicated during mitosis? Here’s another passage from the same source, and I don’t pretend to understand it:

The most important event occurring in S phase is the replication of DNA. The aim of this process is to produce double the amount of DNA, providing the basis for the chromosome sets of the daughter cells. DNA replication begins at a point where regulatory pre-replication complexes are attached to the DNA in the G1 phase. These complexes act as a signal for where DNA replication should start. They are removed in the S phase before replication begins so that DNA replication doesn’t occur more than once.

Canto: Wow. That explains not much. Obviously the key to it all is the ‘regulatory pre-replication complexes’ previously attached. How could I not have known that?

Jacinta: Well let’s just say that there are known mechanisms by which DNA replication is regulated, and prevented from occurring more than once in the S phase. I’m sure all those ‘pre-replication complexes’ have been named and studied in detail by scores of geneticists. So that’s enough for now about chromosome synthesis/replication. The S phase also involves continued cell growth and the production of more proteins and enzymes for DNA synthesis. Always looking to the future. And so we move to the next phase.

Canto: Ah yes, reading ahead I see that DNA synthesis is always much the same. The DNA double helix is kind of unzipped by an enzyme called helicase, and the two single strands can be used as templates to form new and identical double strands. I’m over-simplifying of course.

Jacinta: Yes there are different processes going on to ensure that everything goes more or less smoothly, as well as to maintain cell growth outside of the genetic material. A key enzyme, DNA polymerase, binds nucleotides to the template strands using the base pairing code – A binds to T, C to G. This creates an identical new double helix of DNA.

Canto: Apparently there’s a difference between DNA replication and chromosome replication. Please explain?

Jacinta: I’m not sure if I can, but we’re talking about the replication of chromosomes in the S phase, after which each chromosome now consists of two sister chromatids (halves of a chromosome), as you see below.

 

In the first circle, A and B are homologous pairs. That’s to say, they’re segments of DNA, chromosomes, from each parent, though they might code differently – they might be different alleles. This is a bit complicated. Sal Khan in his video puts it this way:

Homologous pairs means that they’re not identical chromosomes, but they do code for the same genes. They might have different versions, or different alleles for a gene or for a certain trait, but they code essentially for the same kind of stuff.

Make of that what you will. I suppose it means that the homologous pair might have, say, genes for eye colour, but mum’s will code for blue, dad’s for brown. But the same kinds of genes are paired. Anyway, after replication in the S phase, you get, as above, two male and two female chromosomes, joined together in a sort of x shape. They’re joined together at that circular sort of binding site called a centromere (it’s not actually circular). The images above are misleading though, in that there are short arms and long arms leading off the centromere. You could say the centromere is off-centre. So the whole of this new x-shaped thingy is called a chromosome and each half – the right and the left – is called a chromatid. And at the four ends of the x-shaped thingy – I mean the chromosome – is a cap of repetitive DNA called a telomere.

Canto: Ah yes, I’ve heard of those and their relation to ageing…

Jacinta: Let’s not be diverted. So all of this is occurring in the nucleus, and there’s also replication of the centrosomes. Okay they’re a new structure I’m introducing, one that seems to only occur in animal-type or metazoan eukaryotic cells. They serve as microtubule organising centres (MTOCs), according to Wikipedia, which is never wrong, and which goes into great detail on the structure of these centrosomes, but for now the key is that they’re essential to the future separation of the chromatids via microtubules during prophase I. And that’s the next phase to describe. And it’s worth noting that the developments described up to now could be preliminary to meiosis or mitosis.
So, in prophase I the nuclear envelope starts to disintegrate and the pair of centrosomes are somehow pushed apart, to opposite sides of the chromosomal material, and microtubule spindles start extending from them – presumably by the magic of proteins. And another sort of magical thing happens, though I’m sure that some geneticists understand the detail of it all, which is that the homologous pairs line up on opposite sides of a kind of equator line, guided by these spindles, forming a tetrad, and this is where a process called crossing over or recombination occurs, in which the pairs exchange sections of genes. And this recombination somehow manages to avoid duplication and to maintain viability, and indeed to increase diversity. The recombination occurs at points in the chromosomes called chiasmas.
So that’s the end of prophase I. Now to metaphase 1. In this phase the nucleus has disappeared, the centromeres have completed their move to the opposite sides of the cell, and the spindle fibres of microtubules become attached to chromosomes via the kinetochores – protein structures connected to the centromeres. Here’s an interesting and useful illustration of a kinetochore.

All of this is similar to metaphase in mitosis. Then in anaphase I the homologous pairs, which remember had come together and recombined, are separated, or pulled apart, which is different from anaphase I in mitosis, where the chromosomes are split into their separate chromatids. Next comes telophase I, when the separation is complete, the facilitating microtubules break down and cytokinesis, the final separation of the chromosomes and the cytoplasm into two distinct cells, occurs. Telophase I ends with two cells and two nuclei, each containing 23 chromosomes, half of those in the original cells. They’re called daughter cells, for some reason.

Canto: Probably because son cells sounds silly.

Jacinta: Good point. So now these daughter cells start on a whole new PMAT process, which is a lot more like mitosis. Prophase II involves the disintegration of the nucleus once more, the two centrosomes start to move apart as microtubules are formed – and remember this is happening simultaneously in the two daughter cells – and then we’re into metaphase II, where the centrosomes have migrated to opposite ends of the cell, and the chromosomes line up at the ‘equator’, and the spindle fibres attach to the kinetochores of the sister chromatids. Next comes anaphase II, in which the spindle fibres draw the chromatids away from each other, as in anaphase during mitosis. And at the end of this journey they’re now treated as sister chromosomes. And all of this is happening in those two daughter cells, which start to stretch and cleave, which of course means that, in telophase II, you have cytokinesis, and the creation of new nuclear membranes, and the cytoplasm – remember that all the cytoplasm and its organelles have to be replicated too, to make, in the end four, complete haploid cells, or gametes. So that’s the potted version. There’s lots of stuff I’ve excluded, like the difference between centrosomes and centrioles, and lots of details about the cytoplasm, and there’s no doubt much more to learn (by me at least) about the crossing over that’s so essential to provide the variation that Darwin searched for in vain. Anyway, that was sort of fun and thank dog for the internet.

Canto: But I’m still confused about sperm cells and egg cells… If sperm cells are just those little tadpole things – a bunch of DNA with a flagellum, they don’t have any cytoplasm to speak of, do they?

Jacinta: Ah yes, something to look into. There’s spermatogenesis and there’s oogenesis… for a future post. It just never ends.

References

https://www.thoughtco.com/stages-of-meiosis-373512

https://www.albert.io/blog/what-occurs-in-the-s-phase/
https://en.wikipedia.org/wiki/Centrosome
https://www.thoughtco.com/kinetochore-definition-373543
https://opentextbc.ca/biology/chapter/6-2-the-cell-cycle/
https://www2.nau.edu/lrm22/lessons/mitosis_notes/meiosis.html
https://www.genome.gov/genetics-glossary/Chromatin
https://sciencing.com/difference-between-centriole-centrosome-13002.html

Written by stewart henderson

June 8, 2022 at 10:25 pm

exploring genetics – Mendel, alleles and stuff

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Canto: So I’d like to know as much as I can about genetics before I die, which might be quite soon, so let’s get started. What’s the difference between genetics and genomics?

Jacinta: Okay, slow down – but I suppose that’s as good a place to start as anywhere. I recently listened to a talk about the human genome project, which was completed around 2003, and the number I heard the guy mention was 3 billion genes, or something. But according to videos and other sources, each human has between 20,000 and 25,000 genes – though I’ve found another FAQ which estimates 30,000. So I gather from this that our genome is the number of genes we might possibly have – in the whole human population? Which raises the question, how do we know that the human genome project has captured or mapped all of them.

Canto: So there’s an individual genome, peculiar to each of us, and a collective genome?

Jacinta: Errr, maybe. We’re 99.9% genetically identical to each other, supposedly. And if this sounds very paradoxical, we need to zoom in on the detail. And with that, I’ve discovered that the 3 billion refers to base pairs, sometimes called ‘units of DNA’. So what’s a base pair? Well, we need to start with the structure of DNA, the genetic molecule. That’s deoxyribonucleic acid, which is made up of basic components called nucleotides. A nucleotide of DNA consists of a sugar molecule, a phosphate group and a nitrogenous base. The bases come in four types – adenine, guanine, thymine, and cytosine (A, T, G and C). The sugar and phosphate groups provide structure, allowing the bases to form a long string of DNA. Bonds form between the bases to create a double strand of DNA – hence base pairs.

Canto: Here’s how the World Health Organisation defines genomics, obviously from a health perspective:

Genomics is the study of the total or part of the genetic or epigenetic sequence information of organisms, and attempts to understand the structure and function of these sequences and of downstream biological products. Genomics in health examines the molecular mechanisms and the interplay of this molecular information and health interventions and environmental factors in disease.

Now you might think that this definition could cover genetics too, and maybe we shouldn’t be too worried about the distinction. Maybe, in general, genomics is about sequences of genes, especially in detailing whole organisms, while genetics is more about individual genes.

Jacinta: Genomics is the much more recent term, first coined in the 1980s, whereas genetics and genes date back to before we knew about DNA as the genetic molecule. Going back to Mendel and all, though I don’t think he used the term, he talked about ‘factors’ or some such.

Canto: So we know that there’s DNA, and there’s also RNA, another building block of life. How old are they, and which came first? And can species replicate without these molecules?

Jacinta: Oh dear – we’ll get there eventually, maybe. Genomics deals with the whole complement of genes in an organism, which we’ve gradually realised is necessary to evaluate, say, how prone that organism is to contracting a disease, or developing some immuno-deficiency, because individual genes often don’t tell us much. And there’s also the matter of dominant and recessive genes. Which takes us to inheritance. All those genes are combined together on chromosomes, of which there are 23 pairs in humans, which we inherit from our parents, 23 chromosomes each.

Canto: Combined together? Can you  be more specific?

Jacinta: Okay, a chromosome is a thread-like structure, in which DNA is coiled around structural proteins called histones. Each chromosome has two ‘arms’, flowing from a constriction point called a centromere. These arms are labelled p and q. The p arm is shorter than the q. And these chromosomes contain genes, which may or may not code for proteins. The genes, as mentioned, consist of base pairs, which vary in number from hundreds to millions.

Canto: Okay, so what’s the difference between a gene and an allele?

Jacinta: Well, genes are codes for making proteins – and those proteins affect all sorts of things, to do with taste, smell, hair colour and type, height, and predisposition to various diseases, among many other things. You can call these things ‘traits’, which show up in our phenotype, our physical characteristics. And it should be pointed out that many of these traits are the results of not just one gene but different genes in combination. Now, as mentioned, these genes are in pairs of chromosomes – 23 pairs in humans. Now, say we isolate an area in a chromosome that codes for a particular trait. What about the other chromosome in that pair? Remember, each chromosome comes from a male or female parent, and they are different, genetically – or likely to be. That’s where alleles come in, and it takes us back to Mendel, who found that with pea plants, traits such as colour, or the alleles that carried those traits, could be dominant or recessive. So, for that trait, they could carry two dominant alleles, or two recessive alleles, or one of each. If one or both of those alleles is dominant, the trait will be expressed, but if both are recessive, it won’t be. But as I say, it’s more complicated than that, as traits expressed in phenotypes are generally carried by many genes.

Canto: So alleles are? – how to define them?

Jacinta: Google it mate. Here’s a quickly found definition: “each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome”. So let’s continue with the work of Mendel. When we find a dominant trait, we use a capital, T. It might be paired with another dominant trait, TT, or with a recessive trait, Tt. On the other hand, both traits might be recessive, tt, and that’s all the combos you have, for single traits. Now, in noting this, and the way that alleles combine, Mendel came up with a ‘law of segregation’. Or rather, he noticed a process, which later became recognised as a law. In fact, he observed three fundamental processes, ‘segregation’, ‘independent assortment’, and ‘dominance’, which we now describe as laws. Now, I’ve used the term ‘trait’ but perhaps I should’ve used the term ‘allele’. So TT combines two dominant alleles. The law of segregation has been stated thus:

During gamete formation, the alleles for each gene segregate from each other such that each gamete formed carries only one allele for each gene.

Canto: Right. Uhhh, what’s a gamete again?

Jacinta: Sex cells, which carry only one copy of each chromosome. They’re created during meiosis, after which we end up with four cells each with only one allele for each gene. So indeed, alleles are segregated during gamete formation.

Canto: Oh dear. I’ll have to brush up on meiosis.

Jacinta: So now we have these segregated alleles, which will be recombined. The law of independent assortment comes next. This also occurs during meiosis. In the fourth or metaphase period of cell division, the chromosomes align themselves on the equatorial plane, also called the metaphase plate. This alignment is random, and that’s the key to the law of independent assortment – ‘genes for different traits assort independently of each other during gamete formation’. But obviously Mendel knew nothing about meiosis, though it was first observed in his lifetime, in sea urchins . Anyway, this law allows for many different combinations of alleles depending on how chromosomes become aligned on the metaphase plate. A dihybrid cross will provide more such combinations.

Canto: A dihybrid cross? Please explain.

Jacinta: Well, a monohybrid cross will be like this – TT x tt. Not much to be assorted there. A dihybrid cross might be like this – TtCc x TtCc, creating four different assortments for each cross. So now to the third law, of dominance. This law simply states that ‘some alleles are dominant while others are recessive. An organism with at least one dominant allele displays the effect irrespective of the presence of the recessive one’. So the phenotype will present the dominant allele regardless of whether it’s double-dominant or single-dominant. Though the terms used are homozygous (TT), or heterozygous (Tt).

Canto: So are we going to look at punnett squares now? I’ve heard of them…

Jacinta: Well it might help. They were named after a bloke called Punnett back in 1905, the early days of Mendelian genetics. They’re neat little tables, that can start to get quite complicated, for determining the genotypes of offspring, when you breed dominant with recessive, heterozygous with homozygous and so on. It’s useful for simple genotypes, but when genotypes are multifactorial, as they often are, other methods are obviously required.

Canto: Okay, that’s more than enough to absorb for now.

Jacinta: I think, since we’ve started with Mendel, we might do a historical account. Or maybe not….

References

https://www.google.com/search?client=safari&rls=en&q=alleles&ie=UTF-8&oe=UTF-8

https://byjus.com/biology/mendel-laws-of-inheritance/

https://www.yourgenome.org/facts/what-is-meiosis

 

 

Written by stewart henderson

May 29, 2022 at 8:04 am

Posted in alleles, Mendel

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