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Archive for the ‘genetics’ Category

a bit more on cell cultures, cell mortality and patients’ rights

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Human connective tissue in culture, 500x. Image courtesy of Dr. Cecil Fox (photographer)/National Cancer Institute.

Canto: Well, we’ve followed up Meredith Wadman’s The vaccine race with Rebecca Skloot’s The immortal life of Henrietta Lacks, which intersects with Wadman’s book in describing cell cultures and their value in modern medicine and genetics. So are ready to talk about all this again?

Jacinta: Yes, this book tells a compelling history of the Lacks family as well as a story of the ethics around human cell cultures, based on the HeLa cell line taken from the cervix of Henrietta Lacks in 1951, shortly before she died of cervical cancer.

Canto: A very aggressive adenocarcinoma of the cervix, to be precise, though the tumour was misdiagnosed at the time.

Jacinta: Yes, her bodily state and her sufferings make for grim reading. And the cells were taken sans permission, in a pioneering era of almost no regulation and a great deal of dubious practice.

Canto: The wild west of cell and tissue culturology.

Jacinta: George Gey, the guy who ordered these cells to be taken, was a great pioneer in cancer and cell culture research, but he and others found it very difficult to keep human cells alive in vitro, so he was much surprised and delighted at his success with Henrietta’s tumour cells.

Canto: They were the first ever cells to live beyond the Hayflick limit, though that limit wasn’t spelt out by Hayflick until 1961.

Jacinta: And wasn’t accepted for decades after that. And the reason for their apparent immortality, a rare thing in untreated cells, was their cancerous nature. Human cancer cells contain an enzyme known as telomerase, which rebuilds the telomeres at the ends of chromosomes. Normally these telomeres, often described as like the protective caps at the ends of shoelaces, shorten and so become less protective with each cell division.

Canto: So if we could stop cancer cells from producing telomerase, you’d stop all that metastasising…

Jacinta: Sounds easy-peasy. And if we could introduce telomerase into non-cancerous cells we could all live forever.

Canto: Bet they haven’t thought of that one. So if this cell line was cancerous, how could they be of so much value? How could they be of any use at all, since the aim, I thought, was to produce ‘clean’ cells, like the WI-38 cells Hayflick produced ten years later? Remember how they had so many problems with monkey cells, which were full of viruses?

Jacinta: Well, forget viruses for the moment, the exciting thing about the HeLa cells was that they stayed alive and multiplied, which was rare, and so they could be experimented on in a variety of ways.

Canto: But did they use the cells for vaccines? The 1954 Salk polio vaccine was tested using these cells. How can you do this with cancerous cells?

Jacinta: Well it was the suitability of these cells for mass-production that made them ideal for test-driving the Salk vaccine, and of course their prolific nature was tied to their cancerous nature – Henrietta’s cancer seemed to be horribly fast-spreading, it was just about everywhere inside her at her death. Her cancer was caused by the human papilloma virus (HPV) and I’ve read that this may have had something to do with their prolific nature. She also had syphillis, likely contracted from her philandering husband, and this suppresses the immune system, allowing the cancer cells to multiply more rapidly. But even though they were cancer cells they shared many of the properties of normal cells, including the production of proteins and susceptibility to bacterial and especially viral infections. Of course you would never inject HeLa cells into humans, but their malignancy is an advantage in that you get the results of say, viral infection of cells as they reproduce, much more quickly than with normal cells, because of their reproductive rate. It seems old George Gey hit the jackpot with them, though he never made any more money out of them than the Lackses did.

Canto: They initially used rhesus monkey cells to test their antibody levels in response to Salk’s killed polio virus, but they were too hard to get and too expensive, and the HeLa cells were an excellent alternative because they were easily infected by the virus… and they reproduced with unprecedented alacrity.

The malignancy of immortality (or vice versa). A HeLa cell splitting into two new cells. The green spots are chromosomes. Courtesy Paul D. Andrews)

Jacinta: Yes, that’s to say, they readily produced antibodies, and so could be experimented on to produce the level of antibodies to create immunity. But growing cell cultures in vitro and maintaining them in a viable state, that’s been a decades-long learning process. Tissue culture these days is big business, which has led to the murky ethical questions about tissue ownership that Skloot refers to at the end of her book.

Canto: Yes but I for one am quite clear about that issue. I’m more than happy for researchers to use any tissue that comes from, say, a biopsy done on me. Is that tissue mine, when it’s removed from my body?

Jacinta: Well, is it? Think of locks of hair kept from a loved one – something that happens a few times in Skloot’s book. Wouldn’t you be moved by a lock of hair that you knew came from someone you loved but who was no longer around? Wouldn’t you feel you had hold of a part of her? Not just a memory of her?

Canto: Interesting. I think I’d be in two minds about it. I’d think, yes, this is her hair, a small part of her, and that would bring all the emotion of identity with it. But then, what I know about science and cells tells me this is just hair, it’s not what makes her her. It’s nowhere near it. Our hair is discarded all the time.

Jacinta: If you had some of her brain cells? Or heart tissue haha?

Canto: Nothing but ultra-ultra minuscule parts of the whole. And essentially meaningless when disconnected from that whole. But this misses the point that the value of this tissue for research outweighs by far, to me at any rate, the sentimental value that you’re talking about.

Jacinta: But for some people, and some cultures, the intactness of the human entity, after death say, is of deep-rooted significance. Are you not prepared to respect that?

Canto: But we slough off our trillions of cells all the time. Even as a kid I was told we replace our cells every seven years. Of course it’s much more varied and complicated than that, but the general point of constant renewal is true.

Jacinta: Yes but they’re your cells, with your DNA in them, nobody else’s.

Canto: Well people are prepared to be operated on, which inevitably kills or removes cells, and in doing so they give themselves up to experts in healing their bodies and often saving their lives, so it would seem to me pretty mean-spirited not to allow those experts to make use of what’s removed, which is of no obvious use to them.

Jacinta: I think you have a good argument there, but what if these mad scientists use your cells for some nefarious purpose?

Canto: Well, call me a trusting soul, but why would they do that? And what nefarious purpose could they use them for?

Jacinta: Well it mightn’t even be nefarious. With the modern commercialisation of cell and gene technology, they might find your tissue perfect for developing something patentable, out of which they make shitloads of money while preventing independent research on the tissue, so using your cells in a way that you might strongly disapprove of. But you wouldn’t have the slightest say, as things stand today. Rebecca Skloot describes examples of this kind in the Afterword to her book. There’s been a raging debate about commercialisation and gene patents and patients’ rights for some time now in the USA, and no doubt elsewhere, with scientists and other stakeholders ranged along the spectrum. In fact, these are the last words of Skloot’s book, published in 2010:

2009: More than 150,000 scientists join the American Civil Liberties Union and breast cancer patients in suing Myriad Genetics over its breast-cancer gene patents. The suit claims that the practice of gene patenting violates patent law and has inhibited scientific research.

Canto: Right. As her investigations reveal, it’s not just about patients wanting a share of the loot from research on their cells, and so using the courts to bog everything down and hinder that research, it’s often about researchers themselves wanting to cash in, and patients joining with other researchers to try to free up the system for the common good. So how’s the Myriad Genetics case going, and how’s the situation regarding patient rights in this field, several years on?References

Jacinta: Well in the case of Myriad, it was all highly complex and litigious, with suits and countersuits, which the company mostly lost, in particular in a landmark (and unanimous) Supreme Court decision of 2013, in which they found that ‘merely isolating genes that are found in nature [in this case the BRCA-1 and BRCA-2 genes] does not make them patentable’. But of course this wasn’t so much about patients’ rights in the material that was once part of their bodies. It’s not all about money – though much of it is, and if you don’t want the money landing in lawyers’ pockets, the best thing is to have clear guidelines, disclosure, and fully developed and complex consent procedures. My impression from doing a fairly shallow dive on the issues is that we’re a long way from sorting this out, in an increasingly complex and lucrative field. Our own federal government’s NHMRC has a booklet out, available on PDF, called ‘Ethics and the exchange and commercialisation of products derived from human tissue: background and issues’, which is already six years old, but I don’t see anything in the legislative pipeline.

Canto: Looks like an issue to be followed up, if we have the stomach for it.

Jacinta: It pays to be informed, that’s one obvious take-away from all this.

Rebecca Skloot, The immortal life of Henrietta Lacks, 2010
Meredith Wadman, The vaccine race, 2017

Written by stewart henderson

July 3, 2017 at 12:22 pm

how evolution was proved to be true

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The origin of species is a natural phenomenon

Jean-Baptiste Lamarck

The origin of species is an object of inquiry

Charles Darwin

The origin of species is an object of experimental investigation

Hugo de Vries

(quoted in The Gene: an intimate history, by Siddhartha Mukherjee)

Gregor Mendel

I’ve recently read Siddhartha Mukherjee’s monumental book The Gene: an intimate history, a work of literature as well as science, and I don’t know quite where to start with its explorations and insights, but since, as a teacher to international students some of whom come from Arabic countries, I’m occasionally faced with disbelief regarding the Darwin-Wallace theory of natural selection from random variation (usually in some such form as ‘you don’t really believe we come from monkeys do you?’), I think it might be interesting, and useful for me, to trace the connections, in time and ideas, between that theory and the discovery of genes that the theory essentially led to.

One of the problems for Darwin’s theory, as first set down, was how variations could be fixed in subsequent generations. And of course another problem was – how could a variation occur in the first place? How were traits inherited, whether they varied from the parent or not? As Mukherjee points out, heredity needed to be both regular and irregular for the theory to work.

There were few clues in Darwin’s day about inheritance and mutation. Apart from realising that it must have something to do with reproduction, Darwin himself could only half-heartedly suggest an unoriginal notion of blending inheritance, while also leaning at times towards Lamarckian inheritance of acquired characteristics – which he at other times scoffed at.

Mukherjee argues here that Darwin’s weakness was impracticality: he was no experimenter, though a keen observer. The trouble was that no amount of observation, in Darwin’s day, would uncover genes. Even Mendel was unable to do that, at least not in the modern DNA sense. But in any case Darwin lacked Mendel’s experimental genius. Still, he did his best to develop a hypothesis of inheritance, knowing it was crucial to his overall theory. He called it pangenesis. It involved the idea of ‘gemmules’ inhabiting every cell of an organism’s body and somehow shaping the varieties of organs, tissues, bones and the like, and then specimens of these varied gemmules were collected into the germ cells to produce ‘mixed’ offspring, with gemmules from each partner. Darwin describes it rather vaguely in his book The Variation of Animals and Plants under Domestication, published in 1868:

They [the gemmules] are collected from all parts of the system to constitute the sexual elements, and their development in the next generation forms the new being; but they are likewise capable of transmission in a dormant state to future generations and may then be developed.

Darwin himself admitted his hypothesis to be ‘rash and crude’, and it was effectively demolished by a very smart Scotsman, Fleeming Jenkin, who pointed out that a trait would be diluted away by successive unions with those who didn’t have it (Jenkin gave as an example the trait of whiteness, i.e. having ‘white gemmules’, but a better example would be that of blue eyes). With an intermingling of sexual unions, specific traits would be blended over time into a kind of uniform grey, like paint pigments (think of Blue Mink’s hit song ‘Melting Pot’).

Darwin was aware of and much troubled by Jenkin’s critique, but he (and the scientific world) wasn’t aware that a paper published in 1866 had provided the solution – though he came tantalisingly close to that awareness. The paper, ‘Experiments in Plant Hybridisation’, by Gregor Mendel, reported carefully controlled experiments in the breeding of pea plants. First Mendel isolated ‘true-bred’ plants, noting seven true-bred traits, each of which had two variants (smooth or wrinkled seeds; yellow or green seeds; white or violet coloured flowers; flowers at the tip or at the branches; green or yellow pods; smooth or crumpled pods; tall or short plants). These variants of a particular trait are now known as alleles. 

Next, he began a whole series of painstaking experiments in cross-breeding. He wanted to know what would happen if, say, a green-podded plant was crossed with a yellow-podded one, or if a short plant was crossed with a tall one. Would they blend into an intermediate colour or height, or would one dominate? He was well aware that this was a key question for ‘the history of the evolution of organic forms’, as he put it.

He experimented in this way for some eight years, with thousands of crosses and crosses of crosses, and the more the crosses multiplied, the more clearly he found patterns emerging. The first pattern was clear – there was no blending. With each crossing of true-bred variants, only one variant appeared in the offspring – only tall plants, only round peas and so on. Mendel named them as dominant traits, and the non-appearing ones as recessive. This was already a monumental result, blowing away the blending hypothesis, but as always, the discovery raised as many questions as answers. What had happened to the recessive traits, and why were some traits recessive and others dominant?

Further experimentation revealed that disappeared traits could reappear in toto in further cross-breedings. Mendel had to carefully analyse the relations between different recessive and dominant traits as they were cross-bred in order to construct a mathematical model of the different ‘indivisible, independent particles of information’ and their interactions.

Although Mendel was alert to the importance of his work, he was spectacularly unsuccessful in alerting the biological community to this fact, due partly to his obscurity as a researcher, and partly to the underwhelming style of his landmark paper. Meanwhile others were aware of the centrality of inheritance to Darwin’s evolutionary theory. The German embryologist August Weismann added another nail to the coffin of the ‘gemmule’ hypothesis in 1883, a year after Darwin’s death, by showing that mice with surgically removed tails – thus having their ‘tail gemmules’ removed – never produced tail-less offspring. Weismann presented his own hypothesis, that hereditary information was always and only passed down vertically through the germ-line, that’s to say, through sperm and egg cells. But how could this be so? What was the nature of the information passed down, information that could contain stability and change at the same time?

The Dutch botanist Hugo de Vries, inspired by a meeting with Darwin himself not long before the latter’s death, was possessed by these questions and, though Mendel was completely unknown to him, he too looked for the answer through plant hybridisation, though less systematically and without the good fortune of hitting on true-breeding pea plants as his subjects. However, he gradually became aware of the particulate nature of hereditary information, with these particles (he called them ‘pangenes’, in deference to Darwin’s ‘pangenesis’), passing down information intact through the germ-line. Sperm and egg contributed equally, with no blending. He reported his findings in a paper entitled Hereditary monstrosities in 1897, and continued his work, hoping to develop a more detailed picture of the hereditary process. So imagine his surprise when in 1900 a colleague sent de Vries a paper he’d unearthed, written by ‘a certain Mendel’ from the 1860s, which displayed a clearer understanding of the hereditary process than anyone had so far managed. His response was to rush his own most recent work into press without mentioning Mendel. However, two other botanists, both as it happened working with pea hybrids, also stumbled on Mendel’s work at the same time. Thus, in a three-month period in 1900, three leading botanists wrote papers highly indebted to Mendel after more than three decades of profound silence.

Hugo de Vries

The next step of course, was to move beyond Mendel. De Vries, who soon corrected his unfair treatment of his predecessor, sought to answer the question ‘How do variants arise in the first place?’ He soon found the answer, and another solid proof of Darwin’s natural selection. The ‘random variation’ from which nature selected, according to the theory, could be replaced by a term of de Vries’ coinage, ‘mutation’. The Dutchman had collected many thousands of seeds from a wild primrose patch during his country rambles, which he planted in his garden. He identified some some 800 new variants, many of them strikingly original. These random ‘spontaneous mutants’, he realised, could be combined with natural selection to create the engine of evolution, the variety of all living things. And key to this variety wasn’t the living organisms themselves but their units of inheritance, units which either benefitted or handicapped their offspring under particular conditions of nature.

The era of genetics had begun. The tough-minded English biologist William Bateson became transfixed on reading a later paper of de Vries, citing Mendel, and henceforth became ‘Mendel’s bulldog’. In 1905 he coined the word ‘genetics’ for the study of heredity and variation, and successfully promoted that study at his home base, Cambridge. And just as Darwin’s idea of random variation sparked a search for the source of that variation, the idea of genetics and those particles of information known as ‘genes’ led to a worldwide explosion of research and inquiry into the nature of genes and how they worked – chromosomes, haploid and diploid cells, DNA, RNA, gene expression, genomics, the whole damn thing. We now see natural selection operating everywhere we’re prepared to look, as well as the principles of ‘artificial’ or human selection, in almost all the food we eat, the pets we fondle, and the superbugs we try so desperately to contain or eradicate. But of course there’s so much more to learn….

William Bateson

Written by stewart henderson

June 14, 2017 at 5:42 pm

touching on the complex causes of male violence

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A bout of illness and a general sense of despair about blogging has prevented me from posting here for a while. For my health and well-being I’ll try to get back on track. So here’s a brief post on my hobbyhorse of the moment.

It surprises me that people could try to argue with me about the violence of men compared to women, trying to explain it away in terms of physical size – I mean, really? And then, when this doesn’t fly, they point to individuals of established combativeness, the Iron Lady, Golda Meir, and why not mention Boadicea, or [place name of fave female serial killer here]?
And it really demoralises me when this argumentative cuss is a woman. I mean I love a feisty female but really…
It reminds me of a scenario from my not-so-youth, when I briefly hung out with a perverse young lass who insisted with unassailable feistiness that men were clearly more intelligent than women (by and large, presumably). It certainly made be wonder at how intelligence could be turned against itself. But was it intelligence, or something else?

But let’s get back to reality. Men are more violent than women in every country and every culture on the planet. This is a statistical fact, not a categorical, individual claim. Of course there are violent women and much less violent men. That isn’t the point. The point is that you cannot sheet this home to sexual dimorphism. Two examples will suffice. First, look at death and injury by road accident in the west – in countries where both men and women are permitted to drive. The number of males killed in road accidents is considerably higher than females in every western country. In Australia males are almost two and a half times more likely to die this way than females, and in some countries it’s more, but it’s everywhere at least double. The WHO has a fact sheet On this, updated in November 2016:

From a young age, males are more likely to be involved in road traffic crashes than females. About three-quarters (73%) of all road traffic deaths occur among men. Among young drivers, young males under the age of 25 years are almost 3 times as likely to be killed in a car crash as young females.

The second example is youth gangs, including bikie gangs. These are, obviously, predominantly male, their purpose is usually to ‘display manhood’ in some more or less brutal way, and, again obviously, they can’t be explained away in terms of size difference. Other causes need to be considered and studied, and of course, they have been. Some of these causes are outlined in Konner’s book, but I can’t detail them here because I’ve lent the book out (grrr). An interesting starting point for thinking about the social causes of male violence is found in a short essay by Jesse Prinz here. Prinz largely agrees with Konner on the role of agricultural society in sharpening the male-female division in favour of males, but I think he oversimplifies the differences in his tendency to apply social explanations, and he says nothing about gene expression and hormonal factors, which Konnor goes into in great detail. It seems to me that Prinz’s line of reasoning would not be able to account for the reckless, life-threatening behaviour of young male drivers, for example. While there is clearly something social going on there, I would contend that something biological is also going on. Or something in the biological-social nexus, if you will. Clearly, it’s a very complex matter, and if we can uncover hormonal or neurotransmissional causes, that doesn’t rule out social factors playing a regulatory role in those causes. Social evolution, we’re finding, can change biology much more quickly than previously thought.

Written by stewart henderson

November 6, 2016 at 11:59 am

bonobos and us – lessons to be learnt

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Let’s be sexy about this

Bonobos separated from chimps maybe less than a million years ago, according to some pundits. We haven’t yet been able to determine a more precise date for the split. So which species has changed more? Have chimps become more aggressive or have bonobos become more caring? Is there any way of finding out?
It’s not just about genes its about their expression. It will take some time to work all that out. Brain studies too will help, as we move towards scanning and exploring brains more effectively and less invasively.
But surely we seek not just to understand the bonobo world but to change our own. Who wouldn’t want a world that was less violent, less exclusionary in terms of sex, more caring and sharing, without any loss of the dynamism and questing that has taken us to to the very brink of iphone7?
That last remark will date very quickly… Nah, I’ll leave it in.
So we can learn lessons, and of course we’re already on that path. Advanced societies, if that’s not too presumptuous a term, are less patriarchal than they’ve ever been, without losing any of their dynamism. On the contrary, it can easily be seen that the most male-supremacist societies in the world are also the most violent, the most repressive and the most backward. Some of those societies, as we know, have their backwardness masked by the fact that they have a commodity, oil, that the world is still addicted to, which has made the society so rich that their citizens don’t even have to pay tax. The rest of the world is supporting tyrannical regimes, which won’t change as long as they feel well-fed and secure. Not that I’d wish starvation and insecurity on anyone, but as Roland Barthes once said at one of his packed lectures, the people standing at the back who can’t hear properly and have sore feet must be wondering why they’re here.
Maybe a bit of discomfort, in the form of completely shifting away from fossil fuels for our energy needs haha, might bring certain Middle Eastern countries to a more serious questioning of their patriarchal delusions? Without their currently-valuable resource, they might wake to the fact that they need to become smarter. The women in those countries, so effective on occasion in forming coalitions to defend their inferior place in society, might be encouraged to use their collective power in more diverse ways. That could be how things socially evolve there.
Meanwhile in the west, the lesson of the bonobos would seem to be coalitions and sex. We’ve certainly arrived at an era where sexual dimorphism is irrelevant, except where women are isolated, for example in domestic situations. The same isolation also poses a threat to children. The bonobo example of coalitions and togetherness and sharing of responsibilities, and sexual favours (something we’re a long way from emulating, with our jealousies and petty rivalries) should be the way forward for us. Hopefully the future will see a further erosion of the nuclear family and a greater diversity of child-rearing environments, where single-parent families are far less isolated than they are today, and males want to help and support and teach children because they are children, not because they are their children…

Written by stewart henderson

September 10, 2016 at 6:54 pm

bonobo society, or how to dominate males when you’re smaller

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SLUG; BONOBOS SCIENCE TIMES A BONOBO FAMILY IN A FOREST CLEARING IN WAMBA, ZAIRE. CREDIT: 1996 FRANS LANTING END CURRENT IMAGE 9700023PhotoOWNFREELANCE Photo Caption: Date: 01/01/97 Headline: RETURN NEGS Assignment Caption:RETURN NEGS TO EDITOR/PHOTOG....01/01/97 - 12/31/97 Photographer: FREELANCE Sack Number: 9700023 Reporter: Slug: OWN Desk: Photo Start: 0223 Until: Change Time: False City: State: Country: Location: Contact: Contact Phone: Reporter There?: False Editor: Photo Editor Date Wanted: 01/01/97 Time Wanted: ASAP Summary: Photographer Type: 2 Shot?: False Number of Rolls: 0 Scanned?: 0 Handouts: False Notes: Clean?: False Assignment: 970101028A Record No: 78654


Bonobo society has been closely observed both in captivity and, with much greater difficulty, in the wild, and it’s worth comparing it to that of their close relatives, chimps. It’s clear that, though aggression does exist in bonobo society, it isn’t anywhere near as prevalent as in chimps. This is obviously related to the use, mentioned previously, of sex to reduce tension and aggression in situations which would normally lead to competitive activity. It’s the ‘make love not war’ social system that has caught the attention of many beyond ethological researchers.

Now, it’s clear that aggression in all primate societies comes predominantly from males. Looking at human societies, the statistics are universal. There is no human society on earth where the homicide and/or assault statistics are dominated by females as perpetrators.  Up until very recently it was males who went to war, and today it’s overwhelmingly males who joing gangs, go hoon driving or join terrorist cells, just as in earlier times it was men who journeyed off to the adventure of the crusades or joined Boney’s army to devastate Europe. As Melvin Konner convincingly argues, this strongly indicates a biological or genetic basis for male aggression. Much of it seems to be about the expression in males of androgens, the male sex hormones. Now with the way we’re going today in genetics and biochemistry we may in the future be able to tweak the production of androgens to offer a biological solution to male violence – which is already in decline in developed countries. However, their are other solutions, and Bonobo society represents one.

Bonobo society is very close-knit. Male bonobos develop close lifelong ties with their mothers. There’s no relationship with the father, who’s unknown, as the females engage in sex with multiple partners more or less indiscriminately. Of course males will compete with other males for sexual partners, but even this aggression is damped down by sexual relations between males. It’s as if the button has been found to switch off escalating aggression, and that button is connected to the genitals. It would be intriguing to discover what’s going on in the brain, with neurotransmitters and hormones, during this rise and fall of aggressive emotions.

Sex doesn’t just reduce aggression though. It virtually creates the bonobo social structure. As with chimps, bonobos have a fission-fusion society, breaking off into smaller ‘unit’ groups for hunting and foraging in the forest and coming together in larger groups at other times. Individual associations, apart from the mother-offspring dependency, are casual and changeable. However, the larger group, or community, has its limit, and keeps itself separate from other bonobo communities. Another feature of bonobo society is that females emigrate from their birth groups at around 8 years of age, moving to group of virtual strangers, where they have to work to build relationships, particularly with older females. The female-female bond is a central feature of bonobo society and these bonds become much stronger than in chimp society, in spite of the fact that these females, having come from other groups, are less genetically related than the males. This bond is cemented by sex, which creates loosely hierarchical coalitions, with one female dominating, mostly through reproductive success – especially in the production of males. Sisterhood is powerful, and it’s not necessarily about genetics. It’s a great lesson for our society, if we can get over the idea, so prevalent but hopefully fading, that we’re unique in a more unique way than any other species is unique, that we’re civilized, and that we have little or nothing to learn from our primate cousins.

And there’s so much more to learn, as we’ll see.


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



Written by stewart henderson

September 10, 2016 at 9:03 am

clever Charlie Darwin

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A photo taken by me! King Charles seated in state in the Musuem of Natural History, London. It was a thrill to be granted an audience

A photo taken by me! King Charles seated in state in the Musuem of Natural History, London. It was a thrill to be granted an audience

I recently decided to reread Darwin’s Origin of Species, which was really reading it for the first time as my first reading was pretty cursory, and I could barely follow the wealth of particular knowledge he used for cumulative effect to adduce his theory. This time I’ve been doing a closer reading, and becoming increasingly impressed, and I’ve only read the first chapter, ‘Variation under Domestication’.

Darwin’s argument here of course is that domesticated horses, dogs, birds and plants have been artificially selected over long periods of time, and often unconsciously, to suit human needs and tastes. This might seem screamingly obvious today, and to a degree it was recognised in Darwin’s time, but because of an inability to take the long view, and also because of the then-prevalent paradigm of the fixity of species, breeders and nurserymen tended to under-estimate their own cumulative powers, and to claim, for example, that dogs and pigeons had always come in many varieties. Even Darwin was uncertain, and was willing to concede – writing of course before the advent of Mendelian genetics, never mind the revolution wrought by the identification and analysis of DNA as the molecule of inheritance – that in some cases the breeders might be right:

In the case of most of our anciently domesticated animals and plants, I do not think it is possible to come to any definite conclusion, whether they have descended from one or several species.

He was even prepared to concede that it was ‘highly probable that our domestic dogs have descended from several wild species’, while at the same time arguing that the breeding of dogs, in Egypt, other parts of Africa and Australia (where, in his Beagle travels, he observed dingoes, which he may have seen as semi-domesticated by the Aborigines) extended back far further in time than most people suspected. We now know that Darwin’s concession here was ‘premature’. The latest research strongly suggests that our domesticated dogs trace their ancestry to a group of European wolves dating from 19,000 to 32,000 years ago, and probably now extinct. That’s a time-frame Darwin would’ve baulked at, and it’s both funny and kind of tragic that this is something I’ve ‘discovered’ after 30 seconds of selective internet searching. There’s no doubt, though that Darwin’s bold but always informed speculations were heading in the right direction.

Particularly informed –  and bold – were his speculations about pigeons. This is hardly surprising as he spent several years studying and breeding them himself. Interestingly, he started doing so because he’d become convinced that all the fancy pigeons then on show were most likely derived from one common species, the rock pigeon or rock dove (Columba livia), a view already held by some naturalists but few breeders.  He devotes several pages in Chapter 1 to arguing his case, for example pointing out that the ‘several distinct species’ argued for by breeders can be crossed with complete success, that’s to say with no signs of sterility or more than usually defective offspring.

So, as with dogs, I decided to look up what the latest research was on the ancestry of English carriers, short-faced tumblers, runts, fantails, common tumblers, barbs, pouters, trumpeters and laughers, to name some of the pigeons Darwin mentions in the chapter, and was excited to find that a piece of research published as recently as 2013 has confirmed Darwin’s hypothesis. Cheaper and faster genome sequencing technologies have enabled researchers to sequence the genomes of many wild and domesticated birds, and they’ve found that all of the latter are clearly closer to C livia than to any other wild species. It only took just over 150 years for Darwin to be proven correct.

Close reading like this really does reap some fun rewards, and I’ll finish with two more examples. Darwin wrote of how in the world of breeding, quite a drastic change can be brought about in one breeding step, as in the case of the fuller’s teasel with its hooks. He goes on:

So it has probably been with the turnspit dog; and this is known to have been the case with the ancon sheep.

Not knowing wtf he was talking about, I irritatedly decided to look up these unknown creatures. The turnspit dog is a now-extinct breed, bred specifically from around the 16th century to provide the dogpower to turn meat on a spit, the only conceivable way of cooking large joints of meat in your average fancy household for a couple of centuries. The dog, or dogs, because the system worked better if you had two of them engaged in shift work, turned a wheel by running inside it, rat-like, until the meat was cooked. They were known to be long-bodied and short-legged, but details of how they were bred aren’t known, as they were apparently beneath scholarly consideration. They certainly weren’t seen as cuddly pets – if you treat creatures as slaves it heightens your contempt for then (cf Aristotle) – and they were even taken to church as foot-warmers. They’d disappeared entirely by the end of the 19th century.

It's a dog's life?

It’s a dog’s life?

The ancon sheep was a short-legged type, apparently bred from a single individual in the USA in the late nineteenth century, its short legs having the singular advantage, to some, of curtailing its hopes of freedom by jumping the fence. The term ‘ancon’ has since been used by breeding researchers to describe strains of creatures arising from an individual with the same phenotype.


Written by stewart henderson

June 4, 2016 at 11:00 am

why are our brains shrinking?

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my own brain, squeezed of alcohol

my own brain, squeezed of alcohol

Jacinta: So you know that the average human brain mass, or is it volume, has reduced by  – is it 15%, I can’t remember – over the past 20,000 years or so, right? And there’s this theory that it’s somehow related to domestication, because the same thing has happened to domesticated animals…

Canto: How so..?

Jacinta: Well, we don’t know how so, we just know it’s happened.

Canto: How do we know this? Who says?

Jacinta: Well I’ve heard about it from a few sources but most recently from Bruce Hood, the well-known psychologist and skeptic who was talking on the SGU about a recent book of his, The Domesticated Brain. 

Canto: So the idea is that humans have somehow domesticated themselves, in the same way that they’ve domesticated other species, with a corresponding decrease in brain mass in all these species, which signifies – what?

Jacinta: Well it raises questions, dunnit? What’s going on?

Canto: It doesn’t signify dumbing down though – I read in Pinker’s big book about our better angels that our average IQ is rising in quite regular and exemplary fashion.

Jacinta: Yes, the Flynn effect. Though of course what IQ measures has always been controversial. And they do reckon size isn’t the main thing. I mean look at all those small critters that display so many smarts. For example, rats, octopuses and corvids (that’s to say crows, ravens and some magpies). They all seem to be fast learners, within their limited spheres, and very adaptable. But getting back to the human brain, it seems to be something known mainly to palaeontologists, who have a variety of theories about it, including the ‘we’re getting dumber’ theory, but I’m not convinced by that one. It seems more likely that our brains are getting more organised, requiring less mass.

Canto: So this has happened only in the last 20,000 years?

Jacinta: Or perhaps even less – between 10 and 20 thousand.

Canto: Isn’t that a phenomenally short time for such a substantial change?

Jacinta: I really don’t know. They say it might be partly related to a decrease in overall body size, so that the brain to body ratio remains much the same.

Canto: A decrease in body size? What about the obesity epidemic? And I remember way back when I was a kid reading about how we’d been getting taller with each generation since the Great Depression – or was it the Industrial Revolution? Anyway our improved diet, our era of relative abundance, has led to a change in height, and presumably in mass, in only a few generations.

Jacinta: So now you’re saying that substantial changes can occur in a few generations, let alone 10,000 years?

Canto: Uhhh, yeah, okay, but I wasn’t talking about brain size.

Jacinta: Well why not brain size? Anyway, although there have been those recent changes, at least in the west, the story goes that the planet has warmed since the last ice age, favouring less bulky bodies, less fat storage, more gracile frames.

Canto: So what about domestication, why has this led to decreased brain sizes?

Jacinta: Well this is very complex of course…

Canto: I can think of a reason, though it might not be called domestication, more like socialisation, and outsourcing. You can see it in very recent times, with smart phones – it’s even become an already-stale joke, you know phones are getting smarter so we’re getting dumber. But then we always tend to exaggerate the short-term and the present against the longer view. And yet…. I was on the tram the other night, sitting across from this couple, locked into their phone screens, I mean really locked in, earplugs attached, heads bent, utterly fixated on their little screens, completely oblivious, of each other as well as of the outside world. I was reading a book myself, but I became distracted by my irritation with these characters, while wondering why I should be irritated. It just went on so long, this locked-in state. I leaned forward. I waved my hand in front of their bowed heads. I wanted to tell them that the tram had rattled past all the stations and was heading out to sea…

Jacinta: There are some problems with the whole argument. How do we know that domesticated animals have smaller brains? Domesticated cats have a wide range of brain sizes no doubt, but what wild cats are you comparing them with? Even more so with dogs and their immense varieties. Okay they’re descended from wolves so you compare a wolf brain with its modern doggy-wolfy counterpart, but who’s going to agree on type specimens?

Canto: So you brought the subject up just to dismiss it as a load of rubbish?

Jacinta: Well if we shelve the domestication hypothesis for the moment – I’m not dismissing it entirely – we might consider other reasons why human brains are shrinking – if they are.

Canto: So you’re not convinced that they are?

Jacinta: Well let’s be sceptical until we find some solid evidence. In this Scientific American site, from November 2014, palaeontologist Chris Stringer states that ‘skeletal evidence from every inhabited continent’ suggests – only suggests – that our brains have become smaller in the past 10 to 20 thousand years. No references are given, but the article assumes this is a fact. This piece from Discovery channel or something, which dates back to 2010, relies in part on the work of another palaeontologist, John Hawks, whose website we link to here. Hawks also talks about a bucketload of evidence, but again no references. The original research papers would likely be behind a paywall anyway, and barely intelligible to my dilettante brain….

Canto: Your diminishing brain.

Jacinta: Okay I’m prepared to believe Hawks about our incredible shrinking brains, but is domestication the cause, and what exactly is domestication anyway? Hawks doesn’t go with the domestication hypothesis. In fact the Discovery article usefully covers a number of alternative hypotheses, and of course the shrinking may be due to a combo. In fact that’s more than likely.

Canto: So what’s Hawks’ hypothesis, since we’re supposedly admirers of his?

Jacinta: Well Hawks decided to look more closely at this brain contraction – which is interesting because I was thinking along the same lines as he was, i.e. has it been a uniform contraction, or was there a sudden, quick development, followed by a stagnant period, as you would expect?

Canto: Anyway isn’t brain organisation more important than brain mass? Sorry to interrupt, but haven’t we already established that?

Jacinta: We haven’t established anything, we’re just effing dilettantes remember. Hawks started looking at more recent data, over the past 4000 years or so, to see if he could detect any difference in the encephalisation quotient (EQ) – the ratio of brain volume to body mass – over that time. He found that indeed there has. The picture is complicated, but overall there has been a reduction in the brain compared to the body. His explanation for this though is quite different. He reckons that a series of mutations over recent history have resulted in the brain producing more out of less…

Canto: Right, just as a series of modifications have allowed us to produce smaller but more powerful and fuel-efficient cars.

Jacinta: Uhh, yeah, something like that.

Canto: But we know what those modifications were, we can name them. Can we name the mutations?

Jacinta: Clever question, but we know about cars, we built them and they’ve only been around for a bit more than a century. We know vastly less about the brain and we’re still getting our heads around natural selection, give us a break. Hawks points out that it’s a rule about population genetics well-known in principle to Darwin, that the larger the population the more numerous the mutations, and there was a surge in the human population back when agriculture was developed and large settlements began to form. So a number of brain-related mutations led to streamlining and, as you suggest, fuel efficiency.

Canto: But isn’t this compatible with the domestication hypothesis? I imagine that, if there really is a brain reduction for domesticated animals, it’s because they don’t have to rely on their brains so much for survival, and we don’t either, the collective has sort of magically taken care of it through farming and infrastructure and supermarkets.

Jacinta: Yes but they all have their own complicated networks and issues we have to wrap our brains around. The domestication hypothesis is really about aggression apparently. The argument goes that all animals under domestication become more varied in size, coloration and general build, with a tendency to become more gracile over all. Selection against aggression, according to the primatologist Richard Wrangham, favours a slowly developing brain – one that is, in a sense, in a perpetually juvenile state (think of cute cat and dog videos). Of course, all this assumes that juvenile brains are less aggressive than adult brains, which some might see as a dubious assumption.

Canto: Yes, think of school bullying, Lord of the Flies, youth gangs, the adolescent tendency to extremes…

Jacinta: Well, both Wrangham and Hood offer a particularly interesting example of ‘super-fast’ domestication to illustrate their hypothesis:

In 1958 the Russian geneticist Dmitri Belyaev started raising silver foxes in captivity, initially selecting to breed only the animals that were the slowest to snarl when a human approached their cage. After about 12 generations, the animals evidenced the first appearance of physical traits associated with domestication, notably a white patch on the forehead. Their tameness increased over time, and a few generations later they were much more like domesticated dogs. They had developed smaller skeletons, white spots on their fur, floppy ears, and curlier tails; their craniums had also changed shape, resulting in less sexual dimorphism, and they had lower levels of aggression overall.

Now, how does this relate to juvenilism? Well, in the wild, offspring grow up quickly and have to fend for themselves, which requires a certain ruthless degree of aggression. Cats and dogs, yes, they abandon their offspring soon enough, but those offspring continue to be tutored, tamed, domesticated under their human owners. We hear a lot about school bullying and gangs of youths, but they’re actually the exception rather than the rule, or a last ditch rebellion against the domestication pressure that’s exerted by the whole of society, and they’ll either succumb to that pressure or end up in jail, or worse. It’s a bit like the Freudian concept of sublimation, you channel your aggressive energies into creativity, competitive problem-solving, sports achievements and the like.

Canto: So you’re in favour of the domestication hypothesis?

Jacinta: Well, I’m not against it. It sounds plausible to me. Human domestication, or self-domestication if you want to call it that, is a social-contract sort of thing. You agree to outsource and comply with certain arrangements – laws, government, taxation and so forth, in return for certain benefits in terms of security and resources. So you don’t have to fend for yourself. And that affects the brain, obviously. Though it might not be the whole story.

Written by stewart henderson

April 15, 2016 at 8:42 am