How did Mark Henderson, of The Times, interpret that chimps are more evolved?

…Or rather why did Mark interpret this information that way? I know, I know, rhetorical question, to some extent. I don’t think that we are yet at a stage of comparing genetic sequences to say one organism is more evolved than the other. But Mark Henderson, ‘Science Editor’ of the newspaper

..Comparison of the genomes of the two [humans & chimpanzees] has revealed that many more chimp genes than human ones have been the subject of positive evolutionary selection….

….Chimpanzees have evolved more extensively than humans since the two species split from their common ancestors.

[And this refutes the] anthropocentric view that a grand enhancement in Darwinian selection underlies human origins.”

This conclusion is horribly misleading, and I want to clarify that the number of genes that have been positively selected for, is not the primary mode for evolutionary change. Positive selection sometimes manifests itself in copy number variations, or genes within a genome that have been repeated in order to increase the frequency that transcript will be made. That is what the authors of the original paper compared. But, it is where these changes, duplications for example, are made that ultimately facilitate evolutionary change.

If you are still a bit confused let me try and make a more descriptive explanation. The best analogy that I can come up with right now is that a chimp could have 200 pennies in its hand. That’s $2.00. Some would consider me a human, and I would conversely have 20 dimes in my hand, but that’s also $2.00. The same concept applies with the number of positive selection features within a genome. It’s not how many positive selection artifacts one has, but what one has and where is it in a genome.

In another light, chimps have evolved in a much different time frame and continue to evolve in a much different environment, compared to humans. Different selective pressures may affect more genes being modified in a chimpanzee genome, than one in a human one because we are fundamentally different when looked down to the chromosomal level. So how could we fully compare something like this?

What is so ironic, is that Henderson goes to quote the authors of the paper he is reporting on,

“The study… underlines that evolution is not a matter of progress towards a goal, and that it is incorrect to assume that more intelligent species are “more evolved”.”

So why has he and the editors of The Times published the article with the title that chimps are winning this evolutionary race?

I don’t know. I don’t think anyone knows really. There’s no race! If anyone is ‘winning the evolutionary race’ it is humans, we are unfortunately decimating chimpanzees. But enough ranting. I will hold out to see what the official publication concludes, once its out. All I know is that it will be published in PNAS under the title and link, “More genes underwent positive selection in chimpanzee evolution than in human evolution.”

If you wanna read more about genomic comparisons between humans and other papers, I’ve written a lot about recent papers that discussed this topic. It should be noted that in these recent papers, different conclusions were made from the ones that Henderson is reporting on. So that maybe of interest to you. Here’s a list of links:

Oh yes, how could we have a discussion of genome comparisons of primates without linking up John Hawks? He also writes about positive selection in human-chimpanzee genome comparisons.

Hat tip to Razib, for linking up this article and starting the fire.

5 thoughts on “How did Mark Henderson, of The Times, interpret that chimps are more evolved?

  1. This is as maddening as all the newspaper and TV accounts shouting, “The chimp has 98% the same genes that humans have, and therefore they’re not much different from us…” I would make this analogy. Suppose you wanted to write a complete set of instructions on how to build a building. This would include many volumes on how to find dig rocks out of the ground to find iron ore, and coal etc. to make steel to make nails. How to make hammers, shovels, bulldozers, bricks…how to make paper to write the instructions down…. 98% of the total instruction volumes could be devoted to the gathering of materials. But the 2% engineering and planning instructions would be crucial to the conception of the building project. So too, a very small subset of genes could make a phenomenal difference in the functioning of intelligent planning.

  2. Doug, you’re on the right track.

    You’re dead on about addressing how the concept of chimpanzee and human genome similarities is mildly misrepresented. While 98% similarities may sound very significant, the 2% is millions of base pairs and can be possibly hundreds close thousands of genes.

    Also, almost all living organisms contain homologous genes that make a cell, for example, and surprisingly that’s a lot of our genes. So we share a lot of genes also with the common mouse as well as nematodes.

    But where we differ, and how massive developmental changes are made is in the patterns in which these genes are activated and transcribed into a product. That process raises a whole new level of complexity and points of differentiation that sequence homology does not [yet] address.

    In that manner, sharing sequence homology is only the tip of the massive iceberg that is comparing genomes and phenomes.

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