Humans only 94% similar to chimps, not 98.5%

_{Salvador Cordova

December 28, 2006

Biology, Science}

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There’s a bigger genetic jump between humans and chimps than previously believed

A lot more genes may separate humans from their chimp relatives than earlier studies let on. Researchers studying changes in the number of copies of genes in the two species found that their mix of genes is only 94 percent identical. The 6 percent difference is considerably larger than the commonly cited figure of 1.5 percent.

This makes ReMine’s argument for revisiting Haldane’s Dilemma more compelling because now we’re having to account for how so many nucleotides are fixed in the human and chimp populations such that we have about a 180,000,000 base pair difference from chimps.

Darwinian evolution simply does not have the population resources to fix that many base pairs of difference (not enough individuals, not enough mutations, not enough time). We could of course try to make appeals to neutral theory, but a neutral scenario would also be hard pressed to account for the fixation of that many nucleotides as well…

How does evolution fix into the population things like duplicated genes that have little or no selective advantage via Darwinian evolution? Perhaps not through Darwinian evolution, but through genetic drift in small populations. But how long would that take, and is it consistent with sequence divergences between the duplicated genes and their supposed timelines of origin?

One might appeal to some scenario of rapid neutral evolution followed by an extreme recent bottleneck (so as to account for the low between-same-species sequence diveregence). Furthermore the bottleneck would have to have been simultaneously in effect for both chimps and humans. Heck, the bottleneck would have to be for almost every species out there, and timed appropriately! But would all this be yet another implausible “just so” story?

Haldane’s dilemma has possibly been multiplied by these new discoveries. The population genetics of this should be revisited in light of the new numbers, but I suspect the end conclusion will be difficult for either the Darwinian selectionists or the neutralists or anyone advocating mindless evolution.

HT: David Coppedge at CreationSafaris.com

Comments

Regarding gene duplication or other lenght mutations, Nachman estimates single mutation events may out number length mutation events (like gene duplicaiton) 10 to 1. I could of course have misread his paper, but that does not sound unreasonable. Salscordova_{December 29, 2006
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The following also applies to gene duplication- Dr. Spetner discussing transposons in "Not By Chance":
The motion of these genetic elements to produce the above mutations has been found to a complex process and we probably havenÃ¢â‚¬â„¢t yet discovered all the complexity. But because no one knows why they occur, many geneticists have assumed they occur only by chance. I find it hard to believe that a process as precise and well controlled as the transposition of genetic elements happens only by chance. Some scientists tend to call a mechanism random before we learn what it really does. If the source of the variation for evolution were point mutations, we could say the variation is random. But if the source of the variation is the complex process of transposition, then there is no justification for saying that evolution is based on random events.
And although one might say it is nothing more than personal incredulity, the best way to rectify that would be to demonstrate otherwise.Joseph_{December 29, 2006
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Along the lines of contradiciton-free models, I mentioned Nachman's U-Pardox. I just posted my thoughts on the issue here: Nachman's U-Paradoxscordova_{December 29, 2006
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I've not forgotten about that. Recall I said,
How does evolution fix into the population things like duplicated genes that have little or no selective advantage via Darwinian evolution? Perhaps not through Darwinian evolution, but through genetic drift in small populations. But how long would that take, and is it consistent with sequence divergences between the duplicated genes and their supposed timelines of origin?
What I pointed out is if one argues for gene duplications, if the duplicated genes are highly non-divergent from each other, will it be consistent with the hypothesized neutral mutation rates? Is there a contradiction-free model. I'm skeptical as to whether one even exists... You posed a good question however. Salscordova_{December 29, 2006
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How much poplulation resources will it take to fix 90,000,000 insertions (or duplications or whatever) in one population, and 90,000,000 deletions in another?
Why do you think they were 90,000,000 separate events? Have you forgotten about gene duplication, and things like that? BobBob OH_{December 29, 2006
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We don't even know, because we can't objectively test the premise, whether or not ANY mutation/ selection process can account for the physiological and anatomical differences observed between the two populations, chimps and humans. What does that say about the scientific validity of the statement "chimps and humans share a common ancestor"? (hint: it is pseudo-scientific dogma)Joseph_{December 29, 2006
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I'd like to point out that the issue of fixation of a single DNA nucleotide (or its deletion) is still an issue whether the nucleotide adds function or not. If Chimps have 180,000,000 more base pairs than humans, we have the problem of a comon ancestor from which humans effectively lost 90,000,000 base pairs and Chimps gained 90,000,000 base pairs. Of course, that's the most optimistic scenario! How much poplulation resources will it take to fix 90,000,000 insertions (or duplications or whatever) in one population, and 90,000,000 deletions in another? I would also point out, I'm rather distressed that in all of the evolutionary scenarios that I see offered, I don't see any accounting for the side effects of assumed mutation rates (point, in-del, etc.) or other evolutionary simulation parameters. How much purifying selection or whatever kind of mechanisms required to keep each line somewhat monomorphic (i.e. humans are about 99.5% similar to each other). The are costs associated with maintenance of the genome. They don't even figure into most discussions. I may post on Nachman's U-Paradox soon.scordova_{December 29, 2006
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To avocationist & JGuy, Chimps & Humans; explore the differencesJoseph_{December 29, 2006
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Nice. I always wondered about this sort of thing. The rate of change needed is beyond what RM+NS is able to ever accomodate even in the Darwinists most fevered imaginiation.jwrennie_{December 29, 2006
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... survival of the berzerkiest.JGuy_{December 29, 2006
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"JGuy - these are duplications of genes, so the whole gene gets duplicated in one go. Hence, the fixation events are not independent." - Bob Good argument. I'm not sure whether that makes the situation any worse or better for either side (ID or evolution); for the evolutionary viewpoint, assuming the differences were all gene changes, it argues more that less changes genetic fixes needed to occur. However, it argues against the idea that point mutations are adding any new information to the genome. Post hoc (from my standpoint) it might seem like ID-ist should have predicted that whole genes would make up a very significant portion of the differences... and not point mutations. Though the point mutation would also be interesting to know... so, any new genes would have to be assumed to be from point mutations (just to entertain the evolutionary beast). Anyway, assume the 180Mb are all genes. Assume the average protein is 300-aa. That's alreday an average 900 base pairs. Now, there may be other genetic material associated with the gene. Let's double it to 1800 (haha, and also makes the math a bit easier)... and you have 1800 base pairs per gene (for sake of argument).. this is still at minimum (180Mb/(1.8Kb /gene)) or very roughly 100,000 genes needing to be fixed in 6M years... or 1 new gene fixed in the whole population every 60 years. Assuming a 20 year generation, that's a fixation in the population in 3 generations... seems easier to imagine this way, but still, how is it mathematically and biologically possible to do so? Does one "monkeyguy" decide he's the magic gene bearer and run around killing all the males and impregnating all the cuties? - JGJGuy_{December 29, 2006
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Bob, Thanks for looking into it. I realize there are complications when trying to align and establish % identity. For the reader's benefit, see: Growth of GenBank, 2005 Homo Sapein Genome size = 3,4000,00,000 Pan Troglodytes= 3,577,500,000 That is technically a difference of 177,500,000.scordova_{December 28, 2006
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6% of 3,000,000,000 base pairs. If you have a better figure, I would welcome it.
I suspected something like that. But check the original article: they talk about similarity in genes, not bases. I don't know what a better figure would be, and I'm not sure how you would calculate it with large duplications happening. JGuy - these are duplications of genes, so the whole gene gets duplicated in one go. Hence, the fixation events are not independent. BobBob OH_{December 28, 2006
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So, if human and chimp had a common anscester 6 million years ago.. then the human genome would have had to independently fix in about 90 million changes... (ie. assuming the other 90 million differences come from the common anscester to chimp and no percentage of identical changes). 90Mbp/6my = 15 fixed base pairs PER YEAR in the population! Those would be some fast 'monkeys'. Natural Selection would have been busy... as well as the nemapods.JGuy_{December 28, 2006
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Bob, 6% of 3,000,000,000 base pairs. If you have a better figure, I would welcome it. Salscordova_{December 28, 2006
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"Sal - where does your 180,000,000 base pair difference figure come from?" - Bob Bob, I'd assume he multiplied the 3 billion base pairs, the estimate number in the human genome, by 6% [the latest percent difference between human and chimp].JGuy_{December 28, 2006
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Sal - where does your 180,000,000 base pair difference figure come from? BobBob OH_{December 28, 2006
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Of Mice and Men? http://archives.cnn.com:80/2002/TECH/science/12/04/coolsc.coolsc.mousegenome/index.html LOLMario A. Lopez_{December 28, 2006
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BTW: I guess this does away with the good arguemnt Jonathan Wells used.. that if chimps are only 1.5% different than us genetically.. then how do you explain the vast differences? I'll miss that argument. But it's being replaced with a probably a mroe hurtful argument to evolutionary thinking... as I'm sure they will miss arguing that we are 98.5% similar to chimps genetically. It's good to see movement/progress in our knowledge though.. I'm confident in the direction, but doubt purely materialistic evolutionists are as comfortable.JGuy_{December 28, 2006
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"I read somewhere that it is not possible to have intermidiate forms between quadrupedalism and bipedalism, is that true?" - IDist I don't know. However, I have read that for the ape-like anscestor to evovle to a human would require some hard core upper spinal/cranial adaptation... I don't know how else to state that.. anyway, the human skull rests on top of the spine, where-as the chip skull is situated forward of the spine (not resting upon the spinal column). This modification is not something trivial.. what could be intermediate.. a skull hanging on the edge of the spine ???????? Someone more well versed in this could do well to correct me...and clarify what I am hitting around. Thanks.JGuy_{December 28, 2006
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Salvador, offtopic, but thought you would enjoy :) http://uwnews.washington.edu/ni/article.asp?articleID=29019 Wnt signal processing... they're excited about potential human benefits.Michaels7_{December 28, 2006
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We have a different mode of locomotion (weÃ¢â‚¬â„¢re bipedal).
I read somewhere that it is not possible to have intermidiate forms between quadrupedalism and bipedalism, is that true? besides, I think quadrupedalism has a higher survival value. The apes can move faster and easier than we do, and we can not jump from a tree to a tree like chimps :D.IDist_{December 28, 2006
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I knew it. One difference that I think is important, but what do I know, is that we have 46 chromosomes and the apes have 48. There's quite a list of differences between humans and apes. We have a different mode of locomotion (we're bipedal). We are relatively hairless, and the hair we do have is of a different pattern than apes (we have more on the chest, less on the back) we have long head hair, a very modified face and jaw, they see well at night, they pant, we sweat, they do not cry tears, they do not have subcutaneous fat attached to the skin, human females have permanent breasts, they cannot swim, and they are much stronger pound for pound. There are many differences in physique. Oh, and we have a modified pharnyx and laynx, allowing us to speak (and choke easily on our food.) And that's without even starting on the brain. That's a lot of differences between two supposedly really closely related species. And yet I am told that mice and rats are more different than humans and chimps. Does anyone understand how that can be? Other than size, I can't think of any such major structural differences between those two.avocationist_{December 28, 2006
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Ã¢â‚¬Å“I could have told you thatÃ¢â‚¬Â This comment gave me a good laugh. And also let me just add, duh! IÃ¢â‚¬â„¢d expect even greater differences will be found in the future because, as Jehu so eloquently put it, Ã¢â‚¬Å“chimps are hairy little animals and humans are notÃ¢â‚¬Âshaner74_{December 28, 2006
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Now the genomes of men and chimp have been sequenced it has become clear chimp is not as closely related as believed by the Darwinian community. About a decade ago Roy Britten showed the genomes' sequences differed by at least 5% percent (counting indels), instead of the 1-2% percent usually propagated. Last year it was reported that humans have three dozen unique protein coding genes when compared to chimps and now we find that of the 244 newly discovered microRNA genes 10% are unique to humans (not found in any other organism). Chimp also has unique microRNA genes. Apparently, this "junk" makes the species. At last we know. reference: http://www.nature.com/ng/journal/v38/n12/full/ng1914.html
By Peter Borger http://www.iscid.org/boards/ubb-get_topic-f-6-t-000681.htmlIDist_{December 28, 2006
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There's a bigger genetic jump between humans and chimps than previously believed.
I could have told you that. For starters, chimps are hairy little animals and humans are not. Some people have become so completely hypnotized by Darwinism they miss this simple common sense fact. :)Jehu_{December 28, 2006
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How do you like the phrase "The new finding supports the idea that evolution may have given humans new genes with new functions that don't exist in chimps" We should be more grateful to mother Evolution for all she has so richly bestowed upon us.idnet.com.au_{December 28, 2006
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