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Calling classicists please

 
  

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Evil Scientist
07:59 / 02.09.05
However it isn't even a particularly accurate critique of humans in general. Unless we agreed that humans should have an additional taxonomic name to represent the specific social group in which they existed. In which case it might be applicable to some people.

Is it appropriate to do this for a species with such a varied and complicated social structure as humans? Does the marked difference in behavioural and social patterns between groups influenced by politics, religion, etc, mean that we are not one species but countless sub-species? By making that assumption we would obviously be risking people from certain groups being labelled as "sub-species".

It's a risky thing to assign value judgements of that magnitude to species descriptions.
 
 
sdv (non-human)
12:57 / 02.09.05
Evil,

contary to your point about the dangers of humans being labelled as 'sub-species', it is critical to accept that we should not be constructing a heirachy of value on the basis of which species you belong to.

Given your technoscientific bias - I would suggest to you that is is critical to recognise that as a 'species' we still function as if other species are in competition with us. (excepting perhaps the occasional virus and bacteria)...

The logic of neo-darwinism (see John Gray for example) is that species are mere names and don't in fact exist outside of the naming system.

There is nearly as much intra-species conflict between humans as there is inter-species conflict between humans and the species we are making extinct and abusing on a daily basis.
 
 
Evil Scientist
20:36 / 02.09.05
But surely, by your labelling of humans as nothing more than consumers, you are doing just this, albeit in a negative rather than positive way. Can you see where I'm coming from on this?

If Homo sapiens seems too much like Humanity trying to express superiority (and if so, then why?) over the rest of the lifeforms on the planet then why not suggest a taxonomic description that is more accurate?

See, it's precisely my technoscientific bias that's crying out for a description of the species that makes no value judgements and, in fact, describes what we are.

I'm curious how neo-Darwinism backs up it's claim that animals don't exist outside of their classification. Sounds more like a philosophical attitude than a scientific one.
 
 
sdv (non-human)
06:42 / 06.09.05
Evil,

Neo-darwinism is a doctrine that emerges from science, it teaches is that species are only assemblages of genes (dna, rna etc). That these interact with each other and their changing environments. The consequence of this is that neo-darwinism argues that species cannot control their destinies because their purpose (in the last instance) is to be the carriers of genes. Further that logically species cannot exist - because of the last instance. This applies to all living things including humans. Neo-darwinism does not believe that evolution is selecting for phentotypic fitness, but rather for the continuation of genes, selection and continuation of genes may depend on the interaction of genes with other genes - but does not depend on the continuation of species.

Humans emerge out of evolutionary processes that are blind and undirected. To believe in species and to mix this up with a notion 'progress of humanity' is to believe in a construct that develops out of christian myths and has no place in a world where truth should be judged against scientific and philosophical methods.

The very human logic supremacy is well enough known and the numbers of human and non-human deaths high enough to enable us to easily recognize that it is as redundent, perhaps even more so even than 'religious faith'...
 
 
Lurid Archive
11:16 / 06.09.05
Can you name any "neo-darwinists", sdv? Because I can't think of any, OTTOMH. Clearly, you are borrowing heavily from Dawkins, but you can't be intending Dawkins as an example of "neo-darwinism" in your particular sense since I am fairly sure that he believes that species exist (though one has to be careful about what is meant by "exist", here, since one can plausibly argue that species are not well defined).

Really, given that species can be defined quite simply (having the potential to breed), it is hard to imagine how anyone would deny their existence. On top of that, if you take into account the importance of cladistic taxonomy in providing evidence for evolution, it becomes hard to imagine a "neo-darwinist" who isn't rather sceptical of evolution. Which is odd.

Another advocate of materialism and evolution is Pinker, who has written a fair amount on the subject. Again, I can't see how your term "neo-darwinist" could apply to him either, largely because although he meets some of the criteria you set out, he would accept none of the conclusions.

Humans, and any species, are at some level driven by the "selfish gene". But both Pinker and Dawkins make quite explicit the fact that this does not mean that humans are simply automatons. We can decide what to do, sometimes in ways that are at odds with what our "selfish genes" would want. Probably the most obvious false step I can see sdv is when you say:

To believe in species and to mix this up with a notion 'progress of humanity'

Certainly, no biologist confuses the hierarchy of species with a value hierarchy, despite the inclinations to do so arising from the confusion between technical and natural language uses of "evolution".
 
 
sdv (non-human)
15:38 / 06.09.05
Actually firstly the comment 'progress of humanity' was directed at Evil... who plainly does believe in the progress of humanity. As does, for example E.O.Wilson who foolishly imagines that developments in genetic will enable human beings to take control of their own evolutionary development.

I'll respond to the other comments later
 
 
Lurid Archive
16:29 / 06.09.05
Wait a minute, lets clarify what is referred to by "progress of humanity". By some measures, and I think this should be uncontroversial, humans have progressed. (Unless one wants to claim that no advances in medicine or technology count as "progress" then this is a no-brainer.)

This is not to say that such progress is inevitable, nor that such progress applies to every aspect of existence. But one can reasonbaly "believe in it", under a certain interpretation of the terms.

...E.O.Wilson who foolishly imagines that developments in genetic will enable human beings to take control of their own evolutionary development.

You've lost me sdv. Is this foolish because of the social and environmental dangers inherent in such a project? Or is it foolish because it will never actually be possible?

The former sounds reasonable to me, the latter sounds rather rash.
 
 
sdv (non-human)
18:28 / 06.09.05
It is foolish because it is an ideological claim, which like many such claims that have been made by scientists within the scientific community, will almost certainly not be delivered. It may appear 'rash' - but the list of claims that have not been delivered is growing longer by the day - usually I think of them as implicit or even explicit bids for research money.

On the neo-darwinism issue - it was not my intention to suggest that humans or non-humans are 'automatons' - sorry if that was how it read.

I do regard Dawkins etc as neo-darwinists - a term that aims to group those scientists and philosophers who implicitly follow Wilson who asked 'is the organism DNA's way of making more DNA ?' or as Dawkins puts it organisms are 'the surival machines of genes'.This perspective does exist in a variety of forms across a range of evolutionary thinkers - and whilst they may not explicitly state that species do not exist - however once you begin to suggest that in the last instance we (and bertrand the cat) are organisms/machines in Wilson and Dawkins sense then the differentiation that the notion of species requires seems deeply questionable.

Of course - my original probably unstated reason for refusing the notion of species - is because the alternative is to start thinking in terms of speciesism, which i would rather avoid...

Hope that's clearer...
 
 
Lurid Archive
19:45 / 06.09.05
It is foolish because it is an ideological claim, which like many such claims that have been made by scientists within the scientific community, will almost certainly not be delivered.

It is true that there are lots of claims made which have not been delivered, but you aren't really distinguishing on any scientific basis, or are you? I mean, I could say that I expect a manned mission to mars sometime in the future, and you would say that is an ideological claim? Thats an odd use of language, if you ask me. Partly, I don't really see what you are saying, since presumably your denial that a control of evolution is equally ideological. I guess I don't see what the ideology is beyond the specific instance, and so it doesn't really tell me anything.

I do regard Dawkins etc as neo-darwinists

Fair enough. But then you should probably make it clear that the claims you are making for them aren't ones that they would themselves accept. Partly, I must confess that I think you have probably misunderstood their perspective. For instance,

The consequence of this is that neo-darwinism argues that species cannot control their destinies because their purpose (in the last instance) is to be the carriers of genes.

This "last instance", an ultimate cause which is somehow inescapable is really a misreading of "selfish genes". Pinker, as a good evolutionary psychologist in the Dawkins mold, takes great pains to explain how "genes" exert a sort of pressure with effects that give rise to emergent behaviour on a large scale. The fact that, from a certain perspective, we are gene propogating machines in no way denies the validity of love as a concept and an emotion. There is no conclusion I can see that one can draw about the ability of species to "control" their destiny. (I am just taking a best guess as to what that last phrase means).

Do you really believe that Dawkins, the world renowned polemecist, thinks that we can do nothing to effect politics, morality and the well being of our species and others? Of course not.

Partly, you might put it down to emergent behaviour. The base level (gene replicators) can give rise to more complex structures that have their own terminology. The existence of one does not preclude the other - this is really a extremely common phenomenon. For instance, I don't attempt to understand how to operate Microsoft Word by looking at electron interactions. And I don't see my browser and my email program as indistinguishable just because they are ultimately sets of instructions for a silicon processor, or particular instances of a universal turing machine, if you like.

Similarly, I don't see how noting that cats and trout cannot mate gives rise to speciesism.
 
 
sdv (non-human)
10:40 / 08.09.05
The differend being drawn out between us in the last couple of notes is probably not reconcilable, because our understandings of the claims being made are so different. I take your point about 'emergent behavior'...

Whether they accept the meaning of neo-darwinism as I am using it is irrelevant because this merely identifies that scientists and supporting philosophers sometimes refuse the implications of their own statements.

However with the ideological claims I was thinking about the rather more fanciful and dangerous claims that are constantly being made: examples are nuclear power during the 50s and 60s, current absurd claims being made for genetics and recently stem cell research. What I am suggesting is that such claims should be understood as ideological - which would include the proposition that 'humanity' (for which read 'through science') can take control of it's future evolutionary development. I'm not sure how you misunderstood me as suggesting that I believed this was not an ideological proposition, just my bad prose I suppose...

(This does not mean that I am against science or research - just that we should not believe in statements that do not have any supporting evidence...and which like things nuclear can be extremely dangerous.)

This has diverged dangerously from the original topic, but it's probably more interesting for all that...
 
 
Evil Scientist
12:44 / 08.09.05
SDV, what you describe here sounds more like transhumanist philosophy rather than Dawkinism (what you call, probably accurately, neo-Darwinism).

You won't be surprised to hear that, at heart, I consider myself aligned with the transhumanist way of thinking. I really don't see what's so bad about using technology to improve ourselves (but that's probably a discussion for another thread).

A lot of the scientific community agree with you that we shouldn't be making outlandish claims about the "miracles of genetic engineering and stem cell technologies". Only a few days ago Lord Winston (aka The Happy Stalin) lambasted stem cell researchers for making over-hyped claims about the possible applications of this area of science. His main complaint is that, if the researchers don't come up with the goods, then they're going to get crucified by their critics.

Unfortunately. The critics of this brand of research tend to over-hype their side of the argument. So the public relations departments of both sides get into an ever-esculating cold war. It's the way of the world currently, and it would be far better if it wasn't necessary.
 
 
Lurid Archive
14:52 / 08.09.05
Whether they accept the meaning of neo-darwinism as I am using it is irrelevant because this merely identifies that scientists and supporting philosophers sometimes refuse the implications of their own statements.

I think it tends to be a good rule of thumb that if you ascribe a position to another as unavoidable, yet which they themselves do not accept, you are probably thrashing at straw men. Here, I am pretty sure that the implications you see as inevitable arise out of your own misunderstandings.

I'm not sure how you misunderstood me as suggesting that I believed this was not an ideological proposition, just my bad prose I suppose...

No, my bad typos. I meant to write... presumably your denial that a control of evolution is *possible* is equally ideological.

To clarify, I don't understand what function "ideological" serves. Unless you develop the properties of the ideology, I'm afraid all I'm getting is your expression of disagreement. For instance, I think that true artificial intelligence is possible. (Though with heavy qualifications.) Is that ideological? How? In what way does that statement bear any relation to my view on nuclear power or biotechnology?

This does not mean that I am against science or research - just that we should not believe in statements that do not have any supporting evidence..

But the statement that we will one day have the technology to modify ourselves at the genetic level - our evolution, if you will - has an awful lot of supporting evidence. (Whether it will happen within our lifetimes is a bit more suspect, but I didn't notice that as a qualification.) It may be wrong, but that surely can't be the content of your label "ideological". Also, scientific research involves some measure of speculation, in the form of aspirational goals. On one level it almost seems as if you are objecting to that.
 
 
sdv (non-human)
15:26 / 12.09.05
Lurid/evil,

I'm not sure that this is the place or time to discuss the implications of accepting the meaning of a discourse in terms that are acceptable to the author. I am entertained at the idea of understanding and reading anyone that literally.

I am not constructing a truth/ideology difference here - truth as Badiou amongst others has pointed out again recently is a very rare commodity indeed, whereas ideology is an everyday and all encompassing thing. Science as an ideology ,and by default technoscience often confuses it's propositions and "laws" with truth, but this is not correct because science and it's laws always remain testable and consequently falsifiable. All to often however scientific statements are mere sentences that have no such value, because as in the case of the AI reference they can never be falsified. (Stengers rather than Popper by the way). Such statements are ideological statements which may be justified if supporting evidence ever arrives but this rarely happens.

When a scientist makes a positive proposition that "human control over our evolution" - not only are they presenting the proposition that this is technologically possible, but also that this 'transhumanist' (as Evil put it) process has a value within science and that this proposition should be allowed to "colonize our everyday lives", as if the concept was true, possible and desirable. The ideology is especially apparrant in the cases where the proposition is presented as 'inevitable' (for example the technological singularity) and what is even more serious it is presented as unfalsifiable.
 
 
Lurid Archive
15:45 / 13.09.05
I'm not sure that this is the place or time to discuss the implications of accepting the meaning of a discourse in terms that are acceptable to the author. I am entertained at the idea of understanding and reading anyone that literally.

Errrmm, I'm saying that your are presenting a gross misrepresentation, probably underpinned by your own misunderstanding, which ignores both the expertise and stated opinions of the person you are criticising. I'm not sure that really commits me to an especially 'literal' reading or a particular "meaning of a discourse".

Science as an ideology ,and by default technoscience often confuses it's propositions and "laws" with truth, but this is not correct because science and it's laws always remain testable and consequently falsifiable.

But this "Science" as ideology isn't science as practiced by any scientist I know. The second part of your point is universally accepted by actual scientists, to the point where it would be considered banal.

Similarly, your attempt to conflate possibility with desirability (the is/ought distinction) more or less presupposes a detailed political position out of nothing. For instance, my statement about AI said nothing about the desirability of such. And the same goes for human controlled evolution. While you have no basis for constructing these positions, your resistance to accept an author's words in describing their own opinions tends to insulate your interpretation from challenge.
 
 
sdv (non-human)
21:14 / 13.09.05
Lurid ... " ignores both the expertise and stated opinions of the person you are criticising..." except I am not criticising a person but critiquing a position and consequently questioning a position and an understanding of the world. When you work either in engineering or in philosophy it's never a person but a concept or an argument that is being interrogated....

It seems as if science, which is after all postmodernity and modernity's most favored form of knowledge is unquestionable for you.
 
 
Lurid Archive
22:38 / 13.09.05
except I am not criticising a person but critiquing a position and consequently questioning a position and an understanding of the world.

which you attribute to people (Dawkins) despite their espousing a contrary position. I mean, I'm happy to join you in criticising the position you have outlined, I just don't recognise it as anything but a straw man. This recognisability seems rather obviously pertinent, no matter how committed one might be to the freedom to interrogate positions.

It seems as if science, which is after all postmodernity and modernity's most favored form of knowledge is unquestionable for you.

Without wanting to be snarky, it seems fairly elementary to me that rejecting a particular line of criticism does not entail rejecting all criticism.
 
 
sdv (non-human)
09:32 / 14.09.05
Lurid,

could you explain what line of critique or line 'line of criticism' is acceptable then ?
 
 
Lurid Archive
14:37 / 14.09.05
Sorry, is that a serious question sdv?

Well for starters, since we seem to be talking past each other, let me try an analogy. Imagine, if you will, a criticism of the "Humanities". I think you'll agree that this is a touch tricky, since there is no uniform monolith of thought and opinion available to criticise.

Scientists, in my experience, vary widely in their political disposition and general outlook with regards to ethics, politics, the environment and so on.

So it is perfectly possible to criticise scientists for failing to pay enough heed to environmental concerns, or the influence of business, say. But one should remember that these criticism are unlikely to be plausible if applied indiscriminately to the general category of scientists, never mind "science".
 
 
sdv (non-human)
16:04 / 14.09.05
I'm not sure what the difficulty is about the question. I can see how we have very different understandings about the issues we have discussed previously and radically disagree about science, technoscience and their practices. But I thought that I'd been specific...

So to try a different approach - how then would you imagine constructing a critique of science. Not of their non-scientific views which whilst they obviously must affect how a scientist carries out their work/practice may not be relevant in critiquing science and it's practices --- i was thinking more of things like a sociology of scientific knowledge -- the impacts of which might be to put into question what a law might be, or question if and how a given piece of research is carried out.

The question I asked then was specifically related to what a critique of science and scientific practices might like like for you...

is that clearer ?
 
 
Lurid Archive
09:32 / 15.09.05
A sociology of scientific knowledge would be a huge and rather difficult undertaking due to the technical nature of the beast. This is not to deny that scientific knowledge is in a sense social, subject to personality, fashion and bias. Though a scientist would protest that while the sociology is present, one cannot understand scientific knowledge as a purely social enterprise - your anti-grav device won't work simply by networking and wearing sharp suits.

Questioning what a "law" is, for instance, is all very well and one would probably have to start by seeing what a law is - I can't think of any outside physics and possibly chemistry. This is where my previous point takes hold, since the practices among different scientific disciplines are likely to be quite distinct.

Anyway, the name "law" is clearly a piece of propoganda, one of Newton's contributions I think, and the concept has undergone some change due to the quantum revolution. I'm not sure in what direction one would pursue a critique. For instance, it is now widely accepted that "laws" have a limited domain of application and one can even say they are "wrong" in a certain sense, even though they provide rather startlingly accurate predictive models when they do apply.

But I have no idea what a good critique would look like, at the level you are talking about - one that would have some utility in changing the nature of research apart from secondary ethical concerns - and, as far as I can tell, neither does anyone else.
 
 
grant
14:30 / 03.10.05
According to Portuguese researchers, the main difference between human and ape is hormonal.

The team of researchers propose that the differences observed between apes and humans, and also between different hominids, result from distinct metabolisms in thyroid and sex steroids hormones, such as testosterone (the hormone responsible for male secondary sex characteristics) and estrogens (responsible for female secondary sex characteristics).

Firstly, thyroid and sex steroids are known neuroactive hormones, meaning that they influence the development and function of the brain and so also intelligence. For example, lack of iodine - a crucial precursor for the production of thyroid hormone - results in mental retardation by affecting dopamine, one of the most important neurotransmitters in the organism and known to be crucial for abstract intelligence.

....

Secondly, thyroid and sex steroids can also explain the physical changes occurring concomitantly with brain enlargement during human evolution. Both these type hormones affect body growth - and we know that body increase is an hallmark of human evolution - while sex steroids seem to be responsible for many of the physical changes acquired during this period, such as penis and breast enlargement, development of more sexual differentiated bodies, longer life span and full-time sexual receptivity. These traits also differentiate Homo sapiens from apes.


So, genetically nearly identical, hormonally all different.
 
 
quixote
23:13 / 05.10.05
Ahem (clears throat noisily), my field in biology was systematics, and the whole issue of what constitutes a species or genus is a topic I'm actually a bona fide expert on. (Woo hoo!) Just about the only one topic.

Genus is purely a question of rank, which is another way of saying it's purely a matter of opinion. Some taxonomists define categories broadly, some narrowly, but there is no actual physical reality involved. Personally, I think it would give people a good, swift, and necessary kick in the psychological pants to be members of Pan instead of Homo, but there again, that's a matter of opinion.

Regarding species, there's a lot more debate. To some extent, they're also just categories with no obvious biological reality. In other ways, they really do delimit creatures with separate evolutionary destinies. It's pretty clear that humans aren't going to be interbreeding with other primates, so, unless the genetic engineers really slip the leash, we can be pretty sure of having a separate evolutionary path from everyone else.

So we do need a specific epithet, ie a species name. The whole hand thing is a bit boring. Opposable thumbs are sort-of unique, but also much less interesting that *the* distinguishing feature. We're the most neotenous creature to come along since lampreys decided to stay forever young way back in the Cambrian (I think). We're definitely not terribly sapient, and there are people rising to high office who are barely sentient, so the usual epithet won't do at all, but we can do something with neoteny.

Any votes for Pan neotenus -- or whatever the correct declension is? As the title says, Calling classicists, please!
 
 
Evil Scientist
07:45 / 06.10.05
You'll have to excuse me, no Latin education and wikipedia's being no help either.

Neotenus?
 
 
grant
14:50 / 06.10.05
The Baby Ape.
 
 
*
05:20 / 07.10.05
i.e. we stay children longest, I believe.
 
 
Evil Scientist
09:43 / 07.10.05
Gotcha, not bad. More emotionally neutral than the previous suggestions too.

I have to ask though quixote, when you say that humans are not terribly sapient, what are you comparing us to? Considering we are the most sapient species on the planet (as far as we can currently tell). If there is anything more sapient than us, it isn't talking.
 
 
quixote
02:54 / 08.10.05
re definition of neoteny: sorry, got carried away there. Yes, it means retention of juvenile characteristics after sexual maturity.

As for sapience, I'll grant that some people show evidence of it: all Lithers for instance. :-) But I live in the US and the news here is enough to destroy any faith that humans even think, to say nothing of have wisdom. (Sapientia translates as wisdom, after all.) I think a lot of human history generally suggests that "sapiens" is more a statement of hope than fact. Then there's the recent neurological data showing that the frontal cortex (decision-making) fires *after* the neurons that initiate action. I guess making up good stories after the fact is a unique feature, but it's not usually what we think of when we pride ourselves on being smart.

Seriously though, yes, of course, humans have cognitive abilities not otherwise seen on the planet, but it's mostly a difference in degree rather than kind. The only cognitive trick never detected in another species is grammar. (However, Homo grammaticus would be falsified almost as frequently as Homo sapiens.)
 
 
grant
14:55 / 18.10.05
(I'm not sure if this might not be better in the EQ discussion over here, but this seems a better fit.)

I was just reading Fortean Times yesterday, as I do, and there was a review in the back for a book about human evolution and communication... and music.
The theorist's contention was that human communication started out as singing -- that our hominid ancestors used a holistic, multi-modal, manipulative and musical (Hmmmm) technique of evoking meaning through emotional states. The words followed the tunes.

Humans, he says, were musical apes. Apparently this is also tied to bipedalism -- chimps, who use all four limbs, have no sense of rhythm, it seems. Walking is where we get beats from.


I can't find the Fortean Times piece, but there's another review of The Singing Neanderthals here.
 
 
quixote
02:03 / 19.10.05
The musical ape. I love that idea. I can just see the circle around the campfire after a long day picking berries or digging for clams, and one person starts humming, then another starts tapping on a gourd that dried up next to the fire, and another takes the bass.

It gives me the same feeling as the first time I heard the idea that birds were descended from dinosaurs. Far from being extinct, the dinosaurs were singing in the trees.
 
 
Cat Chant
12:43 / 20.10.05
That's so interesting to me, because it keys into a whole fantasy about gender, language and nature that can be traced through Rousseau (who argues that the original and essential form of language is song, speech is a 'fallen' song and writing is a 'fallen' speech) and ... don't know the person's name, but someone did some research recently and found that when men listen to male voices, they use the part of the brain that's associated with information; when men listen to female voices, they use the part of the brain that's active when listening to music.
 
 
grant
17:24 / 20.12.05
grant said: I remember a Richard Leakey lecture where he quipped something about chimpanzees and humans being a lot more similar than horses and donkeys. Whether they're similar enough to have viable offspring would be... an interesting experiment.

Why, grant, it's very interesting you say that because it turns out, according to some reports, that Stalin thought so too.

from the article: Secret laboratories and ape skeletons have been found in the Black Sea town of Suchumi in Georgia, by workmen building a playground for children.

The bones are thought to come from apes captured in the 1920s and paid for by Stalin, who ordered scientist Ilia Ivanov to carry out the research.

The leader used a French research station in Guinea for the work, where African women were seized to be impregnated with ape sperm.

No pregnancies resulted but the next stage was to implant human sperm in female gorillas.


There's more details about the project in the International Herald-Tribune and MosNews.
 
 
CyberChimp
09:18 / 07.05.06
For those who got involved in the original query which started this thread, I thought the following might be of interest:

http://www.cyberchimp.co.uk/papers/fourhands.htm

Thanks again to everyone who contributed.
 
 
grant
14:34 / 18.05.06
That's a really fun paper -- meant to say that earlier. I like the Kafka quotes (have to dig up that story).

But listen, listen: shocking news has just come over the MonkeyWire (and I'm not making that source up) about the relationship between human and chimpanzee. It's not just Stalin's mad dream -- human ancestors and chimpanzees show signs of interbreeding in the past.

Here's the New York Times coverage, and here's the Washington Post story.

WaPo excerpt: When Nick Patterson of MIT and his colleagues at the Broad Institute compared the genes of humans and chimps, they found that one of the chromosomes -- the female sex chromosome X -- was 1.2 million years younger than the others. It appeared the two species shared a common ancestor who gave them both their X chromosomes, and did so more recently than the ancestors who gave them all the other chromosomes.

The best explanation, the scientists think, is that ancient humans and chimps broke away from each other not once, but twice. The first time was more than 6.3 million years ago. The second time was at least a million years later.

What probably happened was that some of the evolving human ancestors bred with the evolving chimps. This was perhaps not as strange as it seems, for although there were some physical differences between the two groups, "the early humans must have looked pretty much like chimpanzees," said Mallet, the London geneticist.

Males have only one X chromosome, which is necessary for reproduction. As is often the case with hybrids, the male offspring from these unions would probably have been infertile.

But the females, which have two X chromosomes, would have been fertile. If some of those hybrid females then bred with proto-chimp males, some of their male offspring would have received a working X from the chimp side of the family. They would have been fertile -- and with them the hybrid line would have been off and reproducing on its own.

The evolutionary clock indicates this happened no more than 6.3 million years ago, and perhaps as recently as 5.4 million years ago. In that case, the fossils of older species -- such as Toumai, or Sahelanthropus tchadensis, a proto-man from Chad that had a humanlike brow and probably walked on two feet -- must have belonged to descendants of the first human-chimp divergence.

That line must have died out. If it had not, modern man's X chromosome would look as old (or nearly as old) as the other chromosomes.

"I think the most interesting thing [is] this idea that long, extended gene flow seems to have occurred and that this might be a creative mode of evolution," said David Reich, a geneticist at Harvard Medical School. He is one of the authors of the study, which appears in today's issue of the journal Nature.


Pan bimanus indeed!
 
 
alas
14:20 / 22.05.06
I love the fact that one implication of that article is that we owe our existence and complexity to some early acts of "bestiality." Evidence that sexual "perversion" can be both fun and profitable--and is, in fact, sometimes possibly even necessary...
 
 
Evil Scientist
08:32 / 23.05.06
And that's what I'm going to argue in court next week.
 
  

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