Archive for the ‘evolution’ Category
understanding genomics 1 – mitochondrial DNA
Canto: So maybe if we got humans to mate with bonobos we’d get a more promising hybrid offspring?
Jacinta: Haha well it’s not that simple, and I don’t mean just physiologically…
Canto: Okay those species wouldn’t be much attracted to each other – though I’ve heard that New Zealanders are very much attracted to sheep, but that just might be fantasy. But seriously, if two species – like bonobos and chimps, can interbreed, why can’t bonobos and humans? And they’d don’t have to canoodle, you can do it like in vitro fertilisation, right?
Jacinto: Well, bonobos and chimps are much more closely related to each other than they are to humans. And if you think bonobo-human hybridisation will somehow create a female-dominant libertarian society, well – it surely ain’t that simple. What we see in bonobo society is a kind of social evolution, not merely a matter of genetics. But having said that, I’m certainly into exploring genetics and genomics more than I’ve done so far.
Canto: Yes, I’ve been trying to educate myself on alleles, haplotypes, autosomal and mitochondrial DNA, homozygotism and heterozygotism (if there are such words), single nucleotide polymorphisms and…. I’m confused.
Jacinta: Well, let’s see if we can make more sense of the science, starting with, or continuing with Who we are and how we got here, which is mostly about ancient DNA but also tells us much about the past by looking at genetic variation within modern populations. Let me quote at length from Reich’s book, a passage about mitochondrial DNA – the DNA in our mitochondria which is somehow passed down only along female lines. I’ve no idea how that happens, but…
The first startling application of genetics to the study of the past involved mitochondrial DNA. This is a tiny proportion of the genome – only approximately 1/200,000th of it – which is passed down from mother to daughter to granddaughter. In 1987, Allan Wilson and his colleagues sequenced a few hundred letters of mitochondrial DNA from diverse people around the world. By comparing the mutations that were different among these sequences, he and his colleagues were able to construct a family tree of maternal relationships. What they found is that the deepest branch of the tree – the branch that left the main trunk earliest – is found today only in people of sub-Saharan African ancestry, suggesting that the ancestors of modern humans lived in Africa. In contrast, all non-Africans today descend from a later branch of the tree.
Canto: Yes, I can well understand the implications of that analysis, but it skates fairly lightly over the science, understandably for a book aimed at the general public. To be clear, they looked at the same stretches of mitochondrial DNA in diverse people, comparing differences – mutations – among them. And in some there were many mutations, suggesting time differences, due to that molecular clock thing. And I suppose those that differed most – from who? – had sub-Saharan ancestry.
Jacinta: Dating back about 160,000 years, according to best current estimates.
Canto: The science still eludes me. First, how does mitochondrial DNA pass only through the female line? We all have mitochondria, after all.
Jacinta: Okay, I’ve suddenly made made myself an expert. It all has to do with the sperm and the egg. One’s much bigger than the other, as you know, because the egg carries nutrients, including mitochondria, the only organelle in your cytoplasm that has its own DNA. Your own little spermatozoa are basically just packages of nuclear DNA, with a tail. Our mitochondrial DNA appears to have evolved separately from our nuclear DNA because mitochondria, or their ancestors, had a separate existence before being engulfed by the ancestors of our somatic or eukaryotic cells, in a theory that’s generally accepted if difficult to prove. It’s called the endosymbiosis theory.
Canto: So mitochondria probably had a separate, prokaryotic existence?
Jacinta: Most likely, which could take us to the development, the ‘leap’ if you like, of prokaryotic life into the eukaryotic, but we won’t go there. Interestingly, they’ve found that some species have mitochondrion-related organelles with no genome, and our own and other mammalian mitochondria are full of proteins – some 1500 different types – that are coded for by nuclear rather than mitochondrial DNA. Our mitochondrial DNA only codes for 13 different types of protein. It may be that there’s an evolutionary process going on that’s transferring all of our mitochondrial DNA to the nucleus, or there might be an evolutionary reason for why we’re retaining a tiny proportion of coding DNA in the mitochondria.
Canto: So – we’ve explained why mitochondrial DNA follows the female line, next I’d like to know how we trace it back 160,000 years, and can place the soi-disant mitochondrial Eve in sub-Saharan Africa.
Jacinta: Well the term’s a bit Judeo-Christian (there’s also a Y-chromosomal Adam), but she’s the matrilineal most recent common ancestor (mt-MRCA, and ‘Adam’ is designated Y-MRCA).
Canto: But both of these characters had parents and grandparents – who would be somehow just as common in their ancestry but less recent? I want to know more.
Jacinta: To quote Wikipedia…
… she is defined as the most recent woman from whom all living humans descend in an unbroken line purely through their mothers and through the mothers of those mothers, back until all lines converge on one woman.
… but I’m not sure if I understand that convergence. It clearly doesn’t refer to the first female H sapiens, it refers to cell lines, haplogroups and convergence in Africa. One of the cell lines used to pinpoint this convergence was HeLa, the very first and most commonly used cell line for a multiplicity of purposes…
Canto: That’s the Henrietta Lacks cell line! We read The Immortal Life of Henrietta Lacks! What a story!
Jacinta: Indeed. She would be proud, if she only knew… So, after obtaining data from HeLa and another cell line, that of an !Kung woman from Southern Africa, as well as from 145 women from a variety of populations:
The published conclusion was that all current human mtDNA originated from a single population from Africa, at the time dated to between 140,000 and 200,000 years ago.
Canto: So mt-MRCA is really a single population rather than a single person?
Jacinta: Yeah, maybe sorta, but don’t quote me. The Wikipedia article on this gives the impression that it’s been sheeted home to a single person, but it’s vague on the details. Given the way creationists leap on these things, I wish it was made more clear. Anyway the original analysis from the 1980s seems to be still robust as to the time-frame. The key is to work out when all female lineages converge, given varied mutation rates. So, I’m going to quote at length from the Wikipedia article on mt-MRCA, and try to translate it into Jacinta-speak.
Branches are identified by one or more unique markers which give a mitochondrial “DNA signature” or “haplotype” (e.g. the CRS [Cambridge Reference Sequence] is a haplotype). Each marker is a DNA base-pair that has resulted from an SNP [single nucleotide polymorphism] mutation. Scientists sort mitochondrial DNA results into more or less related groups, with more or less recent common ancestors. This leads to the construction of a DNA family tree where the branches are in biological terms clades, and the common ancestors such as Mitochondrial Eve sit at branching points in this tree. Major branches are said to define a haplogroup (e.g. CRS belongs to haplogroup H), and large branches containing several haplogroups are called “macro-haplogroups”.
So let’s explain some terms. A genetic marker is simply a DNA sequence with a known location on a chromosome. A haplotype or haploid genotype is, as the haploid term suggests, inherited from one rather than both parents – in this case a set of alleles inherited together. SNPs or ‘snips’ are differences of a single nucleotide – e.g the exchange of a cytosine (C) with a thymine (T). As to the rest of the above paragraph, I’m not so sure. As to haplogroups, another lengthy quote makes it fairly clear:
A haplogroup is…. a group of similar haplotypes that share a common ancestor with a single-nucleotide polymorphism mutation.More specifically, a haplogroup is a combination of alleles at different chromosomal regions that are closely linked and that tend to be inherited together. As a haplogroup consists of similar haplotypes, it is usually possible to predict a haplogroup from haplotypes. Haplogroups pertain to a single line of descent. As such, membership of a haplogroup, by any individual, relies on a relatively small proportion of the genetic material possessed by that individual.
Canto: Anyway, getting back to mt-MRCA, obviously not as memorable a term as mitochondrial Eve, it seems to be more a concept than a person, if only we could get people to understand that. If you want to go back to the first individual, it would be the first mitochondrion that managed to synthesise with a eukaryotic cell, or vice versa. From the human perspective, mt-MRCA can be best conceptualised as the peak of a pyramid from which all… but then she still had parents, and presumably aunts and uncles…. It just does my head in.
References
https://www.genome.gov/genetics-glossary/Mitochondrial-DNA
https://en.wikipedia.org/wiki/Mitochondrial_Eve
https://en.wikipedia.org/wiki/Haplogroup
Did bonobos do it with chimps? Well, duh
bonobos or chimps? Or both? Or neither? What’s in a name…?
Canto: So we’ve been learning than we did it with Neanderthals, and that Neanderthals did it with Denisovans, and I remember hearing an anthropologist or palaeontologist saying that it’s likely that our split with our last common ancestor with chimps and bonobos – they call it the CHLCA (chimp-human last common ancestor, eliminating bonobos altogether, sigh) – wasn’t necessarily a clean break, which surely makes sense.
Jacinta: Well, yes, as we’ve read, the split was caused by the relatively sudden creation of the Congo River, but the word ‘relatively’, is, well, relative. So this raises the question of speciation in general. Think of those Galapagos finches that so intrigued Darwin. All about differently-shaped beaks, but it didn’t happen overnight.
Canto: Right, so here’s what a website with the rather all-encompassing title “Science” says about our topic:
Tens of thousands of years ago, modern humans slept around with Neandertals and swapped some genes. Now, it turns out one of our closest living relatives, chimpanzees, also dallied with another species. New research reveals that chimps mixed it up with bonobos at least twice during the 2 million years since these great apes started evolving their own identities. Although it’s not yet clear whether the acquired genes were ultimately beneficial or harmful, the finding strengthens the idea that such cross-species mating played an important role in the evolution of the great apes.
Jacinta: Interestingly this Congo River separation which led to a completely different species was repeated by other separations which led to four sub-species of chimps. Which leads me to wonder – what’s the difference between a new species and a sub-species? Why are bonobos ‘deserving’ of being called a different species?
Canto: Well the Science article has some fascinating further information. This was the work of Christina Hvilsom and colleagues, described as ‘conservation geneticists’. They were using any genetic differences they could find to work out where particular chimps were being caught or hunted. But, since the interbreeding of humans and Neanderthals, proven by DNA, had hit the headlines, Hvilsom wondered about the DNA of chimps. So, using the same methods that uncovered Neanderthal in humans –
she and her colleagues determined that 1% of the central chimpanzee’s genome is bonobo DNA. The genetic analysis indicates that this inbreeding happened during two time periods: 1.5 million years ago bonobo ancestors mixed with the ancestor of the eastern and central chimps. Then, just 200,000 years ago, central chimps got another boost of bonobo genes, the team reports today in Science. In contrast, the western chimp subspecies has no bonobo DNA, the researchers note, suggesting that only those chimps living close to the Congo River entertained bonobo consorts.
Jacinta: What this highlights, more than anything to me, is the importance and excitement of genetic and genomic analyses. Not that we’re experts on the topic, but it has clearly revolutionised the science of evolution, complicating it in quite exciting ways. Think again of those Galapogos finches. Separation, some interbreeding, more separation, less interbreeding, but with a few kinks along the way.
Canto: And we’re just beginning our play with genetics and genomics. There’s surely a lot more to come. Ah, to live forever…
Jacinta: So how did they know some inbreeding occurred? Can we understand the science of this without torturing ourselves?
Canto: David Reich’s book Who we are and how we got here tells the story of interbreeding between human populations, and how population genetics has revolutionised our understanding of the subject. With dread, I’ll try to explain the science behind it. First, the Science article quoted above mentions a split between bonobos and chimps 2 million years ago. Others I’ve noted go back only about a million years – for example a Cambridge University video referenced below. The inference, to me, is that there was a gradual separation over a fair amount of time, as aforementioned. I mean, how long does it take to create a major river? Now, I can’t get hold of the data on chimp-bonobo interbreeding in particular, so I’ll try to describe how geneticists detect interbreeding in general.
I’ll look at the human genome, and I’ll start at the beginning – a very good place to start. This largely comes from Who we are and how we got here, and the following quotes come from that book. The human genome consists of a double chain of 3 billion nucleobases, adenine, cytosine, guanine and thymine. That’s 6 billion bases (often called letters – A, C, G and T) in all. Genes are small sections of this base chain (called DNA), typically a thousand or so letters long. They’re templates or codes for building proteins of many and varied types for doing many different kinds of work, although there are segments in between made up of non-coding DNA.
Researchers have been able to ‘read’ these letters via machinery that creates chemical reactions to specific DNA sequences:
The reactions emit a different colour for each of the letters A, C, G and T, so that the sequence of letters can be scanned into a computer by a camera.
What anthropologists want to focus on are mutations – random errors in the copying process, which tend to occur at a rate of about one in every thousand letters. So, about 3 million differences, or mutations, per genome (3 billion genes, coding or non-coding). But genomes change over time due to these mutations and each individual’s genome is unique. The number of differences between two individuals’ genomes tells us something about their relatedness. The more differences, the less related. And there’s also a more or less constant rate of mutations:
So the density of differences provides a biological stopwatch, a record of how long it has been since key events occurred in the past.
As Reich recounts, it was the analysis of mitochondrial DNA, the tiny proportion of the genome that descends entirely down the maternal line, that became a corner-stone of the out-of-Africa understanding of human origins, which had been competing with the multi-regional hypothesis for decades. ‘Mitochondrial Eve’ – a rather ‘western’ moniker considering that the Adam and Eve myth is only one of a multitude of origin stories – lived in Botswana in Southern Africa about 160,000 to 200,000 years ago, given the variability of the genomic ‘clock’ – the mutation rate.
So, what does this have to do with chimps and bonobos? Well, The exact detail of how Hvilsom et al proved that their (slightly) more recent interbreeding events occurred is hidden behind a paywall, and you could say I’m a cheapskate but the reality is I’m quite poor, trying to bring up seven kids and a few dozen grandkids in a home not much bigger than a toilet, so… but truthfully I’m just getting by, and I just want to know in general the techniques used.
First, they have to find ancient specimens, I think. But, in a video referenced below, they raised the question – Can we ‘excavate’ ancient DNA from modern specimens? We’ve learned that many modern humans have a certain percentage of Neanderthal DNA, say around 2%, but each person’s 2% may be different. Aggregating those different segments can, if we analyse the genomes of enough humans, create a whole Neanderthal genome, though not one of any Neanderthal who ever lived! At least that’s how I’m reading it, in my dilettantish way. So what exactly does this tell us? I’m not at all sure – it’s a relatively new research area, and completely new to me.
The presenter of this video uses the heading, at least at the beginning of his talk, ‘A little Archaic introgression goes a long way’. So now I need to know what introgression means. A quick look-up tells me it’s:
‘the transfer of genetic information from one species to another as a result of hybridization between them and repeated backcrossing‘.
I’ve bolded two key words here. Hybridisation, in mammals, is ‘breeding between two distinct taxonomic units’. Note that the term species isn’t used, presumably because it has long been a questionable or loaded concept – life just seems too complex for such hard and fast divisions. Backcrossing seems self-explanatory. Without looking it up, I’d guess it’s just what we’ve been learning about. Canoodling after speciation should’ve ruled canoodling out.
But, looking it up – not so! It’s apparently not something happening in the real world, something like backsliding. But then… Here’s how Wikipedia puts it:
Backcrossing may be deliberately employed in animals to transfer a desirable trait in an animal of inferior genetic background to an animal of preferable genetic background.
This is unclear, to say the least. How could an animal, even a human, deliberately do this? We could do it to other animals, or try it, based on phenotypes. We’ve been doing that for centuries. What follows makes it more or less clear that this is about human experimentation with other animals, though.
Anyway, I’m going well off-topic here. What I wanted to do is try to understand the proof of, or evidence for, bonobo-chimp interbreeding. I accept that it happened, well after the split between these two very similar-looking species. What could be less surprising? Along the way I’ve been reminded inter alia, of homozygous and heterozygous alleles, but I’ve been frustrated that straightforward information isn’t being made available to the general public, aka myself. I’ll pursue this further in later posts.
Jacinta: What a mess. Phenotype isn’t everything my friend. To a bonobo, a chimp probably looks like a neanderthal – a real bonehead… They probably only had sex with them out of pity. ‘Boys, we’ll show you a good time – like you’ve never had before.’
References
https://www.science.org/content/article/chimps-and-bonobos-had-flings-and-swapped-genes-past
David Reich, Who we are and how we got here, 2018
https://www.newscientist.com/article/2110682-chimps-and-bonobos-interbred-and-exchanged-genes/
the evolution of reason: intellectualist v interactivist
In The Enigma of Reason, cognitive psychologists Hugo Mercier and Dan Sperber ask the question – What is reason for? I won’t go deeply into their own reasoning, I’m more interested in the implications of their conclusions, if correct – which I strongly suspect they are.
They looked at two claims about reason’s development, the intellectualist claim, which I might associate with Aristotelian and symbolic logic, premises and conclusions, and logical fallacies as pointed out by various sceptical podcasts and websites (and this can also be described as an individualist model of reasoning), and the interactionist model, in which reason is most effectively developed collectively.
In effect, the interactionist view is claiming that reason evolved in an interactionist environment. This suggests that it is language-dependent, or that it obviously couldn’t have its full flowering without language. Mercier and Sperber consider the use of reason in two forms – justificatory and argumentative. Justificatory reasoning tends to be lazy and easily satisfied, whereas it is in the realm of argument that reason comes into its own. We can see the flaws in the arguments of others much more readily than we can our own. This accords with the biblical saying about seeing motes in the eyes of others while being blind to the bricks in our own – or something like that. It also accords with our well-attested over-estimation of ourselves, in terms of our looks, our generosity, our physical abilities and so on.
I’m interested in this interactionist view because it also accords with my take on collaboration, participatory democracy and the bonobo way. Bonobos of course don’t have anything like human reason, not having language, but they do work together more collectively than chimps (and chimp-like humans) and show a feeling towards each other which some researchers have described as ‘spiritual’. For me, a better word would be ‘sympathetic’. Seeing the value in others’ arguments helps to take us outside of ourselves and to recognise the contribution others make to our thinking. We may even come to realise how much we rely on others for our personal development, and that we are, for better or worse, part of a larger, enriching whole. A kind of mildly antagonistic but ultimately fulfilling experience.
An important ingredient to the success of interactionist reasoning is the recognition of and respect for difference. That lazy kind of reasoning we engage in when left to ourselves can be exacerbated when our only interactions are with like-minded people. Nowadays we recognise this as a problem with social media and their algorithms. The feelings of solidarity we get with that kind of interaction can of course be very comforting but also stultifying, and they don’t generally lead to clear reasoning. For many, though, the comfort derived from solidarity outweighs the sense of clarity you might, hopefully, get from being made to recognise the flaws in your own arguments. This ghettoisation of reason, like other forms of ghettoisation, is by and large counter-productive. The problem is to prevent this from happening while reducing the ‘culture shock’ that this might entail. Within our own WEIRD (from Western Educated Industrial Rich Democratic countries) culture, where the differences aren’t so vast, being challenged by contrary arguments can be stimulating, even exhilarating. Here’s what the rich pre-industrialist Montaigne had to say on the matter:
The study of books is a languishing and feeble motion that heats not, whereas conversation teaches and exercises at once. If I converse with a strong mind and a rough disputant, he presses upon my flanks, and pricks me right and left; his imaginations stir up mine; jealousy, glory, and contention, stimulate and raise me up to something above myself; and acquiescence is a quality altogether tedious in discourse.
Nevertheless, I’ve met people who claim to hate arguments. They’re presumably not talking about philosophical discourse, but they tend to lump all forms of discord together in a negative basket. Mercier and Sperber, however, present a range of research to show that challenges to individual thinking have an improving effect – which is a good advert for diversity. But even the most basic interactions, for example between mother and child, show this effect. A young child might be asked why she took a toy from her sibling, and answer ‘because I want it’. Her mother will point out that the sibling wants it too, and/or had it first. The impact of this counter-argument may not be immediate, but given normal childhood development, it will be the beginning of the child’s road to developing more effective arguments through social interaction. In such an interactive world, reasons need to much more than purely selfish.
The authors give examples of how the the most celebrated intellects can go astray when insufficiently challenged, from dual Nobel prize-winner Linus Pauling’s overblown claims about vitamin C to Alphonse Bertillon’s ultra-convoluted testimony in favour of Albert Dreyfus’ guilt, to Thomas Jefferson’s absurdly tendentious arguments against emancipation. They also show how the standard fallacious arguments presented in logic classes can be valid under particular circumstances. Perhaps most convincingly they present evidence of how group work in which contentious topics were discussed resulted in improvements in individual essays. Those whose essay-writing was preceded by such group discussion produced more complex arguments for both sides than did those who simply read philosophical texts on the issues.
It might seem strange that a self-professed loner like me should be so drawn to an interactionist view of reason’s development. The fact is, I’ve always seen my ‘lonerdom’ as a failing, which I’ve never tried very hard to rectify. Instead, I’ve compensated by interacting with books and, more recently, podcasts, websites and videos. They’re my ‘people’, correcting and modifying my own views thorough presenting new information and perspectives (and yes, I do sometimes argue and discuss with flesh-and-blood entities). I’ve long argued that we’re the most socially constructed mammals on the planet, but Mercier and Sperber have introduced me to a new word – hypersocial – which packs more punch. This hypersocial quality of humans has undoubtedly made us, for better or worse, the dominant species on the planet. Other species can’t present us with their viewpoints, but we can at least learn from the co-operative behaviours of bonobos, cetaceans, elephants and corvids, to name a few. That’s interaction of a sort. And increased travel and globalisation of communications means we can learn about other cultures and how they manage their environments and how they have coped, or not, with the encroachments of the dominant WEIRD culture.
When I say ‘we’ I mean we, as individuals. The authors of The enigma of reason reject the idea of reason as a ‘group-level adaptation’. The benefits of interactive reason accrue to the individual, and of course this can be passed on to other receptive individuals, but the level of receptivity varies enormously. Myside bias, the default position from our solipsistic childhood, has the useful evolutionary function of self-promotion, even survival, against the world, but our hypersocial human world requires effective interaction. That’s how Australian Aboriginal culture managed to thrive in a set of sub-optimal environments for tens of thousands of years before the WEIRDs arrived, and that’s how WEIRDs have managed to transform those environments, creating a host of problems along with solutions, in a story that continues….
Reference
H Mercier & D Sperber, The enigma of reason, 2017
21 – dolphins, bonobos, sex and pleasure
bonobos at Jacksonville zoo
I enjoyed a little boat trip off the north-east coast of Kangaroo Island recently. The owner, our guide, bounced us up and down the shoreline east of Christmas Cove to view caves in the limestone cliffs, seabirds such as wedge-tailed eagles on the cliff-tops, and above all to search for a pod of dolphins known to be using the area as a daytime resting-place.
After a few bouts of bouncing eastward and westward we were becoming skeptical, though by no means annoyed. A year before, the island, Australia’s third largest after Tasmania and Melville Island, had been ravaged by bushfires, devastating vegetation and wildlife, and seriously damaging the island’s fragile economy, not to say ecology, and we were happy to make our tiny contribution without great expectations of sighting fabulous beasties.
So we were delighted, on heading eastward again, to spot a few fins bobbing and dipping in the water ahead. Slowing toward them, we were told there were about 25 dolphins in this pod (the term was first used by whalers in the early nineteenth century, for reasons unknown). I soon gave up trying to count them as identical-looking fins appeared and disappeared and vaguely discerned bodies twisted and turned just below the surface. They seemed to form pairs now and then, breaking the surface sleekly and synchronously in elegant arcs. Dolphins, I learned, spend their days lolling about near the shore in these pods after a night of hunting out at sea. They seemed aware but unconcerned about our presence, and at one time the whole group disappeared then reappeared on the other side of our boat, bobbing and slow-twirling as before.
I was struck by a remark by our guide that dolphins are one of the few mammals that mate for fun or pleasure. Of course I made an immediate connection with bonobos, but then I wondered, what does the verb, to mate, exactly mean? We humans never describe ourselves as mating, that’s for the birds, etc. We fuck, screw, bonk, shag, hump and bone, we more coyly sleep together, and more romantically make love (not allowed for other species), but we’re way above mating.
‘Mating’ brings up two internet definitions, the action of animals coming together to breed, and copulation. So dolphins, and bonobos and humans, often come together to breed – but actually not to breed. As for copulation, that’s rarely used for humans, just as fornication is rarely used for non-humans. The latter is, of course, a term of mostly religious disapproval, and non-humans are too lowly to be worthy of moral judgment.
Of course we do apply mating to humans with a pinch of irony, as in the mating game, and this blurs the line between humans and others, but not enough for me. The point is that dolphins and bonobos use sex, which may not be the full rumpy-pumpy (dolphins don’t even have rumps to speak of), to bond with each other, to ease tension, to have fun, as our guide said. But then, don’t all species have sex purely for pleasure, or at least because driven to do so, by sensation? Do cats, dogs, birds and flies have sex with the intention of reproducing? I don’t think so.
Human sex is pleasurable, so I’ve heard, and I expect bonobo sex is too. Fly sex probably not, or so I thought, but I’m probably wrong. Researchers have found that male fruit flies enjoy ejaculating, and tend to consume alcohol when denied sex. I know exactly how they feel. Anyway, fruit flies have long been favourites for biological research, and more recently they’ve found that ‘a protein present in the ejaculate of male fruit flies activates long-term memory formation in the brains of their female partners’. It rather makes me wonder what effect this kind of research has on the researchers themselves, but I’m sure it’s all for the best.
One thing is certain, cats and dogs, and I’ve had a few, feel pleasure. Cats are appallingly sensual, and I’ve probably had more sexual advances from dogs than from humans, though whether they involved pleasure I can’t be sure. Generally our understanding of non-human sex has expanded in recent decades, as our sense of our specialness in everything has receded. It’s also true that we’ve tended to look at other species with a scientific instrumentalism, that’s to say from the viewpoint of evolution, breeding, genetics and other forms of categorisation, rather from an emotional or sensory viewpoint.
When I was very young I read a book by Ernest Thompson Seton called The biography of a grizzly. This story of Wahb, a male grizzly whose family was wiped out by hunters, and who survived to become the most powerful bear in the region, before inevitable decline and death, had an unforgettable emotional impact. I’m glad I read it though, as, sentimentalised though it might’ve been, it inoculated me against the scientific tendency, now changing, to see any animal as an it, rather than he or she or dad or mum or brother or sister. So this idea of putting oneself in the paws of a grizzly or the feet of a bonobo has long been perfectly legitimate to me.
In 2014 Jason Goldman wrote an article entitled Do animals have sex for pleasure?, in which he cited many instances of other species – bonobos of course heading the list – engaging in oral and penetrative sex ‘out of season’, when pregnancy is precluded. They include capuchin monkeys, macaques, spotted hyenas, bears, lions and fruit bats. It stands to reason that the physiological, whole-of body pleasure we derive from sex is shared by other species, and is indulged by them, and this includes what we call homosex, and masturbation. Australia’s premier science magazine, Cosmos, claimed a few years ago that some 6000 species (or was it 600?) have been observed engaging in homosexual activity, which does sound funny when talking about what we would habitually call lower life forms.
All of these findings have had the effect, and perhaps the intention, of loosening our uptight attitudes toward sex, as well as upending our notions of human specialness. But the behaviour of bonobos, who at times look strikingly like us, is more immediately impactful than anything fruit flies or fruit bats might do. Just the other day I watched a video of bonobos in Jacksonville zoo, Florida. Two of them were lying on the ground close together, and kissing each other, on the lips, again and again. Were they male? female? one of each? Who knows, it was so beautiful to watch.
References
Ernest Thompson Seton, The biography of a grizzly, 1900.
https://www.the-scientist.com/news-opinion/male-fruit-flies-take-pleasure-in-having-sex-30867
https://www.the-scientist.com/news-opinion/sex-promotes-lasting-memories-in-female-flies-66763
Bonobos at Jacksonville Zoo (video)
stuff on human ancestry 1: the australopithecines, mostly
All the evolution we know of proceeds from the vague to the definite
C S Pierce
I was in a bookshop yesterday, where I picked up a copy of Yuval Noah Harari’s book Sapiens and had a gander at the back cover. I read one sentence, which went something like ‘100,000 years ago there were at least six species of Homo sapiens, now there is only one.’ Or maybe it was just ‘six species of Homo‘. It resonated with me, because it’s been a while since I’ve researched and written about the ever-fascinating topic of human origins, a topic that resurfaced for me recently on reading an essay, ‘Lucy on the earth in stasis’ by Stephen Jay Gould in his 1996 collection Dinosaur in a haystack. The essay promoted his ‘punctuated equilibrium’ view of evolution, as it reported that Australopithecus afarensis appeared to be the only hominin type in existence for a period of almost a million years, from approximately 4.9 million years ago to 4 million years ago, after which there was a relatively rapid radiation of hominid species. I could only take the essay on trust, but I maintained the thought that I should investigate whether this claim still held, some twenty-three years later. And that, further, I should investigate whether we were any clearer about our descent, as the last surviving species of that apparent radiation.
And by the way, for my education’s sake I need to straighten out the difference between hominids and hominins. We humans are both, apparently. The hominids, or great apes, include four genera: Pongo, the orang-utangs, of which there are three extant species; Pan, of which there are two species, chimps and bonobos; Gorilla (two species), and Homo, of which there’s only one extant species, but many extinct ones including Neanderthals. The term ‘hominid’ has broadened over time. The term ‘hominin’ is more restrictive, referring only to those species ancestral or related to humans, since the split from the chimp and bonobo line. This explains, I hope, why we are both hominids and hominins. Clearly, though, I should stick to the term hominin for this post, or series of posts.
Anyway, I was surprised to read this claim about the state of human play 100,000 years ago. The old Bill Bryson question, How do they know that? came to mind, but I also felt skeptical, as I seemed to remember that the number was smaller – possibly dependent on whether you were a lumper or a splitter.
We know of course that our closest living relatives are (equally) chimps and bonobos, and the latest dating of our divergence from their line is 4 to 7 million years (according to Wikipedia, but Gould put it at 6 to 8 mya, and this video from the American Museum of Natural History gives it more ‘precisely’ at 7 mya, and another Wikipedia article gives the figure as 6.5 to 5.5 mya, so who knows?) There are a couple of possibilities for our last shared ancestor – Sahelanthropus tchadensis and Orrorin tugenensis – but their more or less competing claims are mired in uncertainty, due to the extreme sparsity of material. It may well be that neither of them fit the bill.
When they look at the evidence from early hominins, researchers are particularly interested in signs of bipedalism, which have been argued to exist in S tchadensis due to the placement of its foramen magnum (the hole in the skull through which the spinal cord passes) towards the back – though this placement has been disputed, quelle surprise. In any case, these earliest hominins evolved during the Pleiocene epoch into the definitely bipedal australopithecines. The bipedal adaptation is so important to the emergence of Homo sapiens that it has been the subject of a great deal of speculation, hypothesis and argumentation. It’s likely that there were a variety of converging factors that favoured this trait’s development. For example, it provided a wider visual field, especially on the ground; it left the hands free to grasp and carry food; it enabled long-distance running, and it reduced the expenditure of energy. However, bipedalism appears to have been a slow development, and early australopithecines such as A afarensis likely spent a lot of time in trees. This is supported by anatomical features such as longer arm-bones, curved fingers, a shallow rib-cage and strong clavicular anchors for brachiation (swinging from the arms among branches).
Over time there were anatomical changes favouring bipedality. These included greater robustness of the ankle and knee joints, and changed positioning of the foramen magnum, the femur and the spine, to support changes to the centre of gravity. But the changes which have had the most long-lasting, even at times dire effects, have been those to the pelvic region. The strengthening and widening of this region, including the ilium, ischium and pubis, to support an upright stance, has to a serious degree compromised the process of childbirth. It’s been observed that australopithecines share with modern humans a sexual dimorphism relating to the lumbar vertebrae, allowing the spinal curvature of females to become more pronounced during pregnancy, which helps to better distribute the weight of the unborn child and to reduce fatigue and maintain stability of posture for the mother. However, the changed shape of the pelvis and the consequent narrowing of the birth canal resulted in what has become known as ‘the obstetrical dilemma’. Unlike virtually every other mammalian species, humans face major difficulties and dangers in childbirth, which require others – midwives or other medical professionals – to assist in the process (for example, neonatal rotation is often necessary for safe delivery). A ‘solution’ to this dilemma, which appears to have evolved over time, is a comparatively short gestation period – the time spent in the womb – to give a greater opportunity for both mother and child to survive the birth. This of course leads to a longer period of childhood dependence as it develops outside the womb. Apparently, a modern human baby is born with approximately 25% of full brain development, compared to 45-50% in other primates. Brain size at birth is limited due to the obstetric dilemma, and greater neoteny is the result.
Encephalisation, which refers to a growth in brain size or mass relative to body size, is now seen as a later development in the human story than bipedalism. Brain size in general has become very questionable as a measure of complex evolutionary development – witness those smart corvids – and it’s worth noting that the Neanderthal brain is on average larger than ours. What’s important, though, is brain structure – something we can’t really look at vis-a-vis our ancestors. However it is reasonable to assume that our much larger brain size compared to australopithecines is largely due to growth in the temporal lobes and the prefrontal cortex. In fact all regions have grown, including the cerebellum, traditionally associated with fine motor control and balance, but more recently connected with cognitive function and language.
But let me return to the hunt for the hominin links from the other great apes to Homo sapiens. In the mid-nineties, two new examples of early hominins were discovered, Australopithicus anamensis and Ardipithecus ramidus. I’m guessing that Gould didn’t know about these discoveries when he wrote his essay, as they seem to have punctured his punctuated equilibrium thesis, at least as regards hominins. Anyway the A anamensis species is believed to have lived from about 4.2 to 3.8 million years ago, and the A ramidus specimens have been dated to around 4.4 million years ago, but interestingly, A afarensis, the principal subject of Gould’s essay, is now believed to have lived from 3.9 million years ago to 2.9 million years ago – that’s a million years after Gould’s stated range. The australopithecines first came to our attention in 1925 when Raymond Dart described Australopithecus africanus from specimens found in South Africa. A africanus is a more gracile type, and may well be in the direct line to humans, though there’s been a lot of dispute about the dating and classifying of different specimens. A africanus is generally thought to be a more recent species than A afarensis, another gracile type. So maybe we can link A africanus back to A afarensis, which in turn can be linked back to S tchadensis, with some intermediate missing links. But then there’s another recently discovered species, Australopithecus sediba, which has been dated to around 2 million years ago and is thought to be a transitional species between A africanus and either Homo habilis (which some prefer to describe as Australopithecus habilis) or Homo erectus. Another gracile species discovered in the nineties, A garhi, dating to about 2.5 million years ago, also seems to fit as a species connecting Australopithecus and Homo. From what I’m reading, the fragmentary nature of these finds, together with obvious questions as to whether particular specimens are typical of whole species (type specimens are often juveniles, which might not be such a good idea), are the main barriers to pinning down the precise lines of succession. That’s why every new discovery is such a treasure.
I haven’t mentioned Ardipithecus or Paranthropus as yet. In the nineties specimens were found in the Afar triangle in East Africa, and classified as Ardipithecus ramidus (around 4.4 million years ago, with uncertain evidence of bipedality, and some evidence of reduced sexual dimorphism) and Ardipithecus kadabba (about 5.6 mya, possibly an ancestor of A ramidus, but known from only a few teeth and bones – the type specimen being a bit of mandible with an attached molar). It’s possible, according to some researchers, that Ardipithecus, Orrorin, and Sahelanthropus all belong to the same genus.
I’ll have a look at Paranthropus, apparently a more robust distant cousin of ours, then move forward to the Homo genus, next time.
References
Australopithecus Evolution (video), by Henry the PaleoGuy, 2019
Seven million years of human evolution (video), American Museum of Natural History, 2018
https://en.wikipedia.org/wiki/Human_evolution
https://en.wikipedia.org/wiki/Australopithecus
https://en.wikipedia.org/wiki/Australopithecus_afarensis
https://en.wikipedia.org/wiki/Australopithecus_africanus
https://en.wikipedia.org/wiki/Australopithecus_sediba
https://en.wikipedia.org/wiki/Australopithecus_anamensis
https://en.wikipedia.org/wiki/Ardipithecus
http://humanorigins.si.edu/evidence/human-fossils/species/ardipithecus-ramidus
a few thoughts on libertarianism
Libertarianism is like Leninism: a fascinating, internally consistent political theory with some good underlying points that, regrettably, makes prescriptions about how to run human society that can only work if we replace real messy human beings with frictionless spherical humanoids of uniform density (because it relies on simplifying assumptions about human behavior which are unfortunately wrong). I don’t know who wrote this.
Aren’t libertarians a lovely lot?
I might look more closely at some libertarian philosophy later, but for now I want to critique the kind of standard libertarianism I’ve heard from politicians and bloggers.
Well, okay, I’ll start with a philosopher, Robert Nozick, whose much-vaunted/pilloried book Anarchy, State and Utopia I tried to read in the eighties. I found it pretty indigestible and essentially learned from others that his argument depended rather too much on one principle – the human right of individuals to certain positive and negative freedoms, but especially negative ones, like the right to be left largely alone, to make their own decisions for example about how to contribute to the greater good. The book ended up advocating for a minimalist state, in which everyone gets to create their own communities of kindred spirits, organically grown A cornucopia of utopias. The kind of state that, ummm, like, doesn’t exist anywhere. That’s the problem. Utopia is definable as a society that only exists in fantasy.
And then there’s the exaltation of the individual. This is the problem I’ve encountered with every libertarian I’ve read or viewed – and I’m quite glad I’ve rarely had any personal encounters with them.
If I did, here would be my response. Homo sapiens are the most socially constructed mammals on the planet. Language has massively facilitated this, and in turn has become our most powerful social product. Common languages have created civilisations, and this has allowed us to dominate the planet, for better or worse. And civilisation requires, or just is, organised social structure. That’s to say, a state, that eternal bogey-man of the libertarian.
This entity, the state, has shaped humans for millennia. Today, we owe (largely) to the state the clothes we wear, the food we eat, the education we’re hopefully still having, the jobs we’ve had and lost, the houses we live in, the cars we used to drive, and the good health we increasingly enjoy. That’s why, it seems to me, we owe it to ourselves to make the state we live in as good as we can make it, in terms of health, safety, opportunity, support, pleasure and self-improvement, for all its members.
It seems to me we have to work with what exists instead of trying to invent utopias – because, obviously, one person’s utopia is another’s nightmare. What exists today is a variety of states, some clearly better than others. The minimalist states are among the worst, and they’re understandably called failed states. There is no effectively functioning minimalist state on the planet, a fact that many libertarians blithely ignore. Their emphasis on individual liberty seems to me the product of either beggar-thy-neighbour selfishness or starry-eyed optimism about natural affinities.
Again, I turn to the USA, my favourite whipping-state. This hotbed of libertarians has not blossomed as it could, considering its booming economy. From this distance, it seems a sad and often stomach-turning mixture of white-collar fraudsters and chronically disadvantaged, over-incarcerated victims, and good people who largely accept this as the status quo. The you-can-achieve-anything mantra of the American Dream generally sees individuals as blank slates who can best fulfil their potential when pulled from the rubble of the coercive state. Or State, as many libertarians prefer.
It didn’t take my recent reading of Robert Sapolsky’s Behave, a superb overview of human behaviour and its multifarious and interactive underpinnings, or Steven Pinker’s earlier The Blank Slate, to realise that this was a dangerous myth. It was always screamingly obvious to me, from my observation of the working-class milieu of my childhood, the variety of skills my classmates displayed and the problems they faced from the outset, together with my readings of more privileged worthies and their patrician connections (Bertrand Russell on the knee of William Gladstone always comes irritatingly to mind), that there has never been anything like an even playing field for exhibiting and making the most of whatever qualities we’re gifted with or are motivated to cultivate and improve.
So this is the problem: we’re not free to undo what has been ‘done to us’ – the parents we have, the country (or century) we’re born in, the traumas and joys we’ve experienced in the womb, our complex genetic inheritance and so forth. All of these things are connected to a much wider world and a past over which we have no control. They shape us (into go-getting libertarians or bleeding-heart liberals or whatever) much more than we’re generally prepared to admit. And these shaping forces, since the emergence of civilisation and that sometimes messily organised unit called the state, are profoundly social. And even if we’re not talking about western civilisation it’s the same – it takes a village to raise a child.
These shaping forces aren’t necessarily bad or good, they just are. But all in all we should be glad they are. The social brain is the brightest, most complex brain, and such brains wouldn’t have developed if the individual was sacrosanct, in receipt of the right to be ‘left alone’. Civilisation is surely the most impressive achievement of human evolution, and as Ralph Adolphs of Caltech puts it, ‘no component of our civilization would be possible without large-scale collective behavior’.
The state, of course, has its drawbacks, as do all large-scale multifaceted administrative entities. The ancient Greek city-states produced a host of brilliant contributors to their own esteem as well as to the world history of drama, philosophy, mathematics and history itself, in spite of being built on slavery and denying any equitable role to women, but even there the (probably few) slaves who worked in the most enlightened households would’ve benefitted from the collective, and the women, however officially treated, were surely just as involved and brainy as the men.
As society has grown increasingly complex we as individuals have grown in proportion, as have our individual delusions of grandeur. At least in some cases. What the best of us should have learned, though, is that a rich, diverse, dynamic society, which cannot but be organised, produces the best offerings to its children. Diminishing the state by refusing to contribute to it actually diminishes and impoverishes the self, diminishes connection and the recognition of collective value. This raises the rather large point that the self isn’t what most people think it is – an autonomous, self-actuated entity. Instead, it is driven by complex social inputs from the very start, indeed from long before it came into being. Just as events from long before a crow is born, or even conceived, will go a long way in determining how that adult crow behaves.
Yet the myth of the individual, autonomous self is a live one, and it’s what drives most libertarians. In so far as people see themselves as self-actualising, they will argue the same for others, and absolve themselves from responsibility for others’ failures, mistakes or incapacities. Such attitudes significantly play down disadvantages of background, and even reduce exposure to those differences. Since everyone has the choice to be as successful as me (according to my own measure of success), why should I waste time hanging out with losers? By that measure, to suggest that silver-spoon libertarians would willingly provide support to disadvantaged communities is as unrealistic as expecting Donald Trump to hang out with the construction workers on his trumpy towers.
In some respects, libertarianism represents the opposite pole to communism, on a continuum that stretches into complete delusion at both ends. There have never been any actual, functioning communist or libertarian states. Both are essentially abstract ideologies, which take little account of the science of evolved human behaviour. When we do take account of that science, we find it is fiendishly complex, with the individual as a unit being driven and shaped by social dependencies, connections and responsibilities, which are generally vital to that individual’s well-being. In western democratic societies, apart from family and workplace organisations, we have government, which includes, in Australia, councils, states and a federation of states. It all sound terribly complex and web-like, and some apparently see it as ‘the enemy of individual liberty’ but in fact it’s the web of civilised human life, which we’ve all contributed to creating, and it’s a pretty impressive web – though more impressive in some places than in others. I think the best thing we can try to do is to improve it rather than trying to extricate ourselves from it. In any case, doing so – I mean, removing ourselves from organised society – just won’t work, and fundamentally misunderstands the nature of our evolved humanity.
kin selection – some fascinating stuff
Canto: So we’ve done four blogs on Palestine and we’ve barely scratched the surface, but we’re having trouble going forward with that project because, frankly, it’s so depressing and anger-inducing that it’s affecting our well-being.
Jacinta: Yes, an undoubtedly selfish excuse, but we do plan to go on with that project – we’re definitely not abandoning it, and meanwhile we should recommend such books as Tears for Tarshiha by the Palestinian peace activist Olfat Mahmoud, and Goliath by the Jewish American journalist Max Blumenthal, which highlight the sufferings of Palestinian people in diaspora, and the major stresses of trying to exist under zionist monoculturalism. But for now, something completely different, we’re going to delve into the fascinating facts around kin selection, with thanks to Robert Sapolski’s landmark book Behave.
Canto: The term ‘kin selection’ was first used by John Maynard Smith in the early sixties but it was first mooted by Darwin (who got it right about honey bees), and its mathematics were worked out back in the 1930s.
Jacinta: What’s immediately interesting to me is that we humans tend to think we alone know who our kin are, especially our extended or most distant kin, because only we know about aunties, uncles and second and third cousins. We have language and writing and record-keeping, so we can keep track of those things as no other creatures can. But it’s our genes that are the key to kin selection, not our brains.
Canto: Yes, and let’s start with distinguishing between kin selection and group selection, which Sapolsky deals with well. Group selection, popularised in the sixties by the evolutionary biologist V C Wynne-Edwards and by the US TV program Wild Kingdom, which I remember well, was the view that individuals behaved, sometimes or often, for the good of the species rather than for themselves as individuals of that species. However, every case that seemed to illustrate group selection behaviour could easily be interpreted otherwise. Take the case of ‘eusocial’ insects such as ants and bees, where most individuals don’t reproduce. This was seen as a prime case of group selection, where individuals sacrifice themselves for the sake of the highly reproductive queen. However, as evolutionary biologists George Williams and W D Hamilton later showed, eusocial insects have a unique genetic system in which they are all more or less equally ‘kin’, so it’s really another form of kin selection. This eusociality exists in some mammals too, such as mole rats.
Jacinta: The famous primatologist Sarah Hrdy dealt something of a death-blow to group selection in the seventies by observing that male langur monkeys in India commit infanticide with some regularity, and, more importantly, she worked out why. Langurs live in groups with one resident male to a bunch of females, with whom he makes babies. Meanwhile the other males tend to hang around in groups brooding instead of breeding, and infighting. Eventually, one of this male gang feels powerful enough to challenge the resident male. If he wins, he takes over the female group, and their babies. He knows they’re not his, and his time is short before he gets booted out by the next tough guy. Further, the females aren’t ovulating because they’re nursing their kids. The whole aim is to pass on his genes (this is individual rather than kin selection), so his best course of action is to kill the babs, get the females ovulating as quickly as possible, and impregnate them himself.
Canto: Yes, but it gets more complicated, because the females have just as much interest in passing on their genes as the male, and a bird in the hand is worth two in the bush…
Jacinta: Let me see, a babe in your arms is worth a thousand erections?
Canto: More or less precisely. So they fight the male to protect their infants, and can even go into ‘fake’ estrus, and mate with the male, fooling the dumb cluck into thinking he’s a daddy.
Jacinta: And since Hrdy’s work, infanticide of this kind has been documented in well over 100 species, even though it can sometimes threaten the species’ survival, as in the case of mountain gorillas. So much for group selection.
Canto: So now to kin selection. Here are some facts. If you have an identical twin your genome is identical with hers. If you have a full sibling you’re sharing 50% and with a half-sibling 25%. As you can see, the mathematics of genes and relatedness can be widened out to great degrees of complexity. And since this is all about passing on all, or most, or some of your genes, it means that ‘in countless species, whom you co-operate with, compete with, or mate with depends on their degree of relatedness to you’, to quote Sapolsky.
Jacinta: Yes, so here’s a term to introduce and then fairly promptly forget about: allomothering. This is when a mother of a newborn enlists the assistance of another female in the process of child-rearing. It’s a commonplace among primate species, but also occurs in many bird species. The mother herself benefits from an occasional rest, and the allomother, more often than not a younger relation such as the mother’s kid sister, gets to practice mothering.
Canto: So this is part of what is called ‘inclusive fitness’, where, in this case, the kid gets all-day mothering (if of varying quality) the kid sister gets to learn about mothering, thereby increasing her fitness when the time comes, and the mother gets a rest to recharge her batteries for future mothering. It’s hopefully win-win-win.
Jacinta: Yes, there are negatives and positives to altruistic behaviour, but according to Hamilton’s Rule, r.B > C, kin selection favours altruism when the reproductive success of relatives is greater than the cost to the altruistic individual.
Canto: To explain that rule, r equals degree of relatedness between the altruist and the beneficiary (aka coefficient of relatedness), B is the benefit (measured in offspring) to the recipient, and C is the cost to the altruist. What interests me most, though, about this kin stuff, is how other, dumb primates know who is their kin. Sapolsky describes experiments with wild vervet monkeys by Dorothy Cheney and Robert Seyfarth which show that if monkey A behaves badly to monkey B, this will adversely affect B’s behaviour towards A’s relatives, as well as B’s relatives’ behaviour to A, as well as B’s relatives’ behaviour to A’s relatives. How do they all know who those relatives are? Good question. The same researchers proved this recognition by playing a recording of a juvenile distress call to a group of monkeys hanging around. The female monkeys all looked at the mother of the owner of that distress call to see what she would do. And there were other experiments of the sort.
Jacinta: And even when we can’t prove knowledge of kin relations (kin recognition) among the studied animals, we find their actual behaviour tends always to conform to Hamilton’s Rule. Or almost always… In any case there are probably other cues, including odours, which may be unconsciously sensed, which might aid in inclusive fitness and also avoiding inbreeding.
Canto: Yes and It’s interesting how this closeness, this familiarity, breeds contempt in some ways. Among humans too. Well, maybe not contempt but we tend not to be sexually attracted to those we grow up with and, for example, take baths with as kids, whether or not they’re related to us. But I suppose that has nothing to do with kin selection. And yet…
Jacinta: And yet it’s more often than not siblings or kin that we have baths with. As kids. But getting back to odours, we have more detail about that, as described in Sapolski. Place a mouse in an enclosed space, then introduce two other mice, one unrelated to her, another a full sister from another litter, never encountered before. The mouse will hang out with the sister. This is called innate recognition, and it’s due to olfactory signatures. Pheromones. From proteins which come from genes in the major histocompatibility complex (MHC).
Canto: Histowhat?
Jacinta: Okay, you know histology is the study of bodily tissues, so think of the compatibility or otherwise of tissues that come into contact. Immunology. Recognising friend or foe, at the cellular, subcellular level. The MHC, this cluster of genes, kicks off the production of proteins which produce pheromones with a unique odour, and because your relatives have similar MHC genes, they’re treated as friends because they have a similar olfactory signature. Which doesn’t mean the other mouse in the enclosure is treated as a foe. It’s a mouse, after all. But other animals have their own olfactory signatures, and that’s another story.
Canto: And there are other forms of kin recognition. Get this – birds recognise their parents from the songs sung to them before they were hatched. Birds have distinctive songs, passed down from father to son, since its mostly the males that do the singing. And as you get to more complex species, such as primates – though maybe they’re not all as complex as some bird species – there might even be a bit of reasoning involved, or at least consciousness of what’s going on.
Jacinta: So that’s kin selection, but can’t we superior humans rise above that sort of thing? Australians marry Japanese, or have close friendships with Nigerians, at least sometimes.
Canto: Sometimes, and this is the point. Kinship selection is an important factor in shaping behaviour and relations, but it’s one of a multiple of factors, and they all have differential influences in different individuals. It’s just that such influences may go below the level of awareness, and being aware of the factors shaping our behaviour is always the key, if we want to understand ourselves and everyone else, human or non-human.
Jacinta: Good to stop there. As we’ve said, much of our understanding has come from reading Sapolsky’s Behave, because we’re old-fashioned types who still read books, but I’ve just discovered that there’s a whole series of lectures by Sapolsky, about 25, on human behaviour, which employs the same structure as the book (which is clearly based on the lectures), and is available on youtube here. So all that’s highly recommended, and we’ll be watching them.
References
R Sapolski, Behave: the biology of humans at our best and worst. Bodley Head, 2017
https://www.britannica.com/science/animal-behavior/Function#ref1043131
https://en.wikipedia.org/wiki/Kin_selection
https://en.wikipedia.org/wiki/Eusociality
how evolution was proved to be true
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
on the long hard road to femocracy
Recently, a list of Australia’s 200 richest people was published. It’s been widely reported that of those 200, only 22 were women; just over 10% – a figure that has apparently held good for some years. But while this is a useful first indication of wealth imbalance along gender lines, it would pay to look more closely at the figures, though this is hard to do, given the secrecy surrounding the wealth of some, and the complexities surrounding and conditioning the wealth of others. Quite a few of these wealthy women appear to be heiresses or ‘sleeping partners’ (in a business sense, but who knows?) rather than active business types, and even leaving this aside, I’m pretty sure that if I could do the maths on all these fortunes, the figure for women would amount to considerably less than 10% of the whole.
These are the Australian figures. Would anybody dare to suggest that the figures for female wealth in China, say, would be any better? (information on wealth in China, like just about any other information from China, is virtually impossible to obtain). Or in Russia – currently rated (by New World Wealth) as the nation with the most unequal distribution of wealth in the world? Just as a guess, I’d expect, or at least hope, that the US and some European nations might be ahead of Australia in terms of female wealth, but if so it surely wouldn’t be by much. Ask a group of students who’s the richest man in the world and you’d get a few unsurprising answers, enthusiastically proclaimed. Ask them about the richest woman, and you’d get puzzled looks as they wonder why you asked such a question.
I’m no economist, and wealth per se isn’t an interest of mine, and I’m much more concerned to get women into leadership positions in science and politics, but clearly having 95% or more of the world’s wealth in the hands of the more fucked-up gender is a big problem, and a huge obstacle to the dethronement of patriarchy.
While I’m not pretending this might happen in the near future, it seems to me that the ultimate solution lies in women’s best weapon – collaboration, or ganging up. The pooling of resources – financial, intellectual, practical, even sexual. I’m not talking about war here, but I am talking about a struggle for power, a slow, persevering struggle built of connections and networks, transcendent of nation, culture, class and age. A struggle not against men but against patriarchy. A struggle which, with ultimate success, will leave all of us winners. You may say I’m a dreamer, but why is a world dominated by woman so absurd when a world dominated by men, the fucked-up world we have now, is apparently not?
http://www.cnbc.com/2016/09/01/russia-is-the-most-unequal-major-country-in-the-world-study.html
three problems with Islamic society, moderate or otherwise
As a teacher of English to foreign students, I have a lot of dealing with, mostly male, Moslems. I generally get on very well with them. Religion doesn’t come up as an issue, any more than with my Chinese or Vietnamese students. I’m teaching them English, after all. However, it’s my experience of the views of a fellow teacher, very much a moderate Moslem, that has caused me to write this piece, because those views seem to echo much that I’ve read about online and elsewhere.
- Homosexuality
It’s well known that in such profoundly Islamic countries as Saudi Arabia and Afghanistan, there’s zero acceptance of homosexuality, to the point of claiming it doesn’t exist in those countries. Its ‘non-existence’ may be due to that fact that its practice incurs the death penalty (in Saudia Arabia, Yemen, Mauritania, Iran and Sudan), though such penalties are rarely carried out – except, apparently, in Iran. Of course, killing people in large numbers would indicate that there’s a homosexual ‘problem’. In other Moslem countries, homosexuals are merely imprisoned for varying periods. And lest we feel overly superior, take note of this comment from a very informative article in The Guardian:
Statistics are scarce [on arrests and prosecutions in Moslem countries] but the number of arrests is undoubtedly lower than it was during the British wave of homophobia in the 1950s. In England in 1952, there were 670 prosecutions for sodomy, 3,087 for attempted sodomy or indecent assault, and 1,686 for gross indecency.
This indicates how far we’ve travelled in a short time, and it also gives hope that other nations and regions might be swiftly transformed, but there’s frankly little sign of it as yet. Of course the real problem here is patriarchy, which is always and everywhere coupled with homophobia. It’s a patriarchy reinforced by religion, but I think if we in the west were to try to put pressure on these countries and cultures, I think we’d succeed more through criticising their patriarchal attitudes than their religion.
Having said this, it just might be that acceptance of homosexuality among liberal Moslems outside of their own countries (and maybe even inside them) is greater than it seems to be from the vibes I’ve gotten from the quite large numbers of Moslems I’ve met over the years. A poll taken by the Pew Research Centre has surprised me with its finding that 45% of U.S. Moslems accept homosexuality (in 2014, up from 38% in 2007), more than is the case among some Christian denominations, and the movement towards acceptance aligns with a trend throughout the U.S. (and no doubt all other western nations), among religious and non-religious alike. With greater global communication and interaction, the diminution of poverty and the growth of education, things will hopefully improve in non-western countries as well.
2. Antisemitism and the Holocaust
I’ve been shocked to hear, more than once, Moslems blithely denying, or claiming as exaggerated, the events of the Holocaust. This appears to be a recent phenomenon, which obviously bolsters the arguments of many Middle Eastern nations against the Jewish presence in their region. However, it should be pointed out that Egypt’s President Nasser, a hero of the Moslem world, told a German newspaper in 1964 that ‘no person, not even the most simple one, takes seriously the lie of the six million Jews that were murdered [in the Holocaust]’. More recently Iran has become a particular hotspot of denialism, with former President Ahmadinejad making a number of fiery speeches on the issue. Most moderate Islamic organisations, here and elsewhere in the west, present a standard line that the Shoah was exactly as massive and horrific as we know it to be, but questions are often raised about the sincerity of such positions, given the rapid rise of denialism in the Arab world. Arguably, though, this denialism isn’t part of standard anti-semitism. Responding to his own research into holocaust denialism among Israeli Arabs (up from 28% in 2006 to 40% in 2008), Sammy Smooha of Haifa University wrote this:
In Arab eyes disbelief in the very happening of the Shoah is not hate of Jews (embedded in the denial of the Shoah in the West) but rather a form of protest. Arabs not believing in the event of Shoah intend to express strong objection to the portrayal of the Jews as the ultimate victim and to the underrating of the Palestinians as a victim. They deny Israel’s right to exist as a Jewish state that the Shoah gives legitimacy to. Arab disbelief in the Shoah is a component of the Israeli-Palestinian conflict, unlike the ideological and anti-Semitic denial of the Holocaust and the desire to escape guilt in the West.
This is an opinion, of course, and may be seen as hair-splitting with respect to anti-semitism, but it’s clear that these counterfactual views aren’t helpful as we try to foster multiculturalism in countries like Australia.They need to be challenged at every turn.
Amcha, the Coalition for Jewish Concerns holds a rally in front of the Iranian Permanent Mission to the United Nations in response to Iranian President Mahmoud Ahmadinejad’s threats against Isreal and denial of the Holocaust, Monday, March 13, 2006 in New York. (AP Photo/Mary Altaffer)
3. Evolution
While the rejection, and general ignorance, of the Darwin-Wallace theory of evolution – more specifically, natural selection from random variation – may not be the most disturbing feature of Islamic society, it’s the one that most nearly concerns me as a person keen to promote science and critical thinking. I don’t teach evolution of course, but I often touch on scientific topics in teaching academic English. A number of times I’ve had incredulous comments on our relationship to apes (it’s more than a relationship!), and as far as I can recall, they’ve all been from Moslem students. I’ve also come across various websites over the years, by Moslem writers – often academics – from Turkey, India and Pakistan whose anti-evolution and anti-Darwin views degenerate quickly into fanatical hate-filled screeds.
I won’t go into the evidence for natural selection here, or an explanation of the theory, which is essential to all of modern biology. It’s actually quite complex when laid out in detail, and it’s not particularly surprising that even many non-religious people have trouble understanding it. What bothers me is that so many Moslems I’ve encountered don’t make any real attempt to understand the theory, but reject it wholesale for reasons not particularly related to the science. They’ve used the word ‘we’ in rejecting it, so that it’s impossible to even get to first base with them. This raises the question of the teaching of evolution in Moslem schools (and of course, not just Moslem schools), and whether and how much this is monitored. One may argue that non-belief in evolution, like belief in a flat earth or other specious ways of thinking, isn’t so harmful given a general scientific illiteracy which hasn’t stopped those in the know from making great advances, but it’s a problem when being brought up in a particular culture stifles access to knowledge, and even promotes a vehement rejection of that knowledge. We need to get our young people on the right page not in terms of a national curriculum but an evidence-based curriculum for all. Evidence has no national boundaries.
Conclusion – the problem of identity politics
The term identity politics is used in various ways, but I feel quite clear about my own usage here. It’s when your identity is so wrapped up in a political or cultural or religious or class or caste or professional grouping, that it trumps your own independent critical thinking and analysis. The use of ‘we think’ or ‘we believe’, is the red flag for these attitudes, but of course this usage isn’t always overt or conscious. The best and probably only way to deal with this kind of thinking is through constructive engagement, drawing people out of the groupthink intellectual ghetto through argument, evidence and invitations to reconsider (or consider for the first time) and if that doesn’t work, firmness regarding the evidence-based view together with keeping future lines of communications open. They say you should keep your friends close and your enemies closer, and it’s a piece of wisdom that works on a pragmatic and a humane level. And watch out for that firmness, because the evidence is rarely fixed. Education too is important. As an educator, I find that many students are open to the knowledge I have to offer, and are sometimes animated and inspired by it, regardless of their background. The world’s an amazing place, and students can be captivated by its amazingness, if it’s presented with enthusiasm. That can lead to explorations that can change minds. Schools are, or can be, places where identity politics can fragment as peers from different backgrounds can converge and clash, sometimes in a constructive way. We need to watch for and combat the echo-chamber effect of social media, a new development that often reinforces false and counter-productive ideas – and encourages mean-spirited attacks on faceless adversaries. Breaking down walls and boundaries, rather than constructing them, is the best solution. Real interactions rather than virtual ones, and thinking about the background and humanity of the other before leaping into the fray (I’m beginning to sound saintlier than I’ve ever really been – must be the Ha Ji-won influence!)