Are orangutans our closest living relatives?
John Hawks: Are orangutans our closest living relatives?
No
My answer would be “it depends” and “some places, yes”, but that answer is a bit more complex…
We’ve been working on the orangutan genome sequence the last year – the genome paper will probably be submitted in a few months and we have a few companion papers on our work on it – and we think we have evidence that some places in the genome humans are closer related to orangutans than chimps (our closest living relatives) and gorillas (our second closests).
So as species, no orangutans are not our closest living relatives – chimps and gorillas, in that order, are closer related to us – but the picture is slightly more complex than this if we look at individual nucleotides in our genome.
It has to do with gene trees vs species trees and so called incomplete lineage sorting.
It is well known that we are mainly closest related to chimps, but quite a large fraction of the genome we are actually closer related to the gorilla. Check e.g.
- Genomic Relationships and Speciation Times of Human, Chimpanzee, and Gorilla Inferred from a Coalescent Hidden Markov Model, Hobolth et al. 2007
- Estimation of Hominoid Ancestral Population Sizes under Bayesian Coalescent Models Incorporating Mutation Rate Variation and Sequencing Errors, Burgess and Yang 2008
We think we see the same for humans and orangutans, but to a much lesser degree of course.
Our paper is still in a rough draft, so I won’t say more about it here…
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181-178=+3
June 30th, 2009 at 12:21 pm
FYI: I’m assuming John Hawks’ post is in response to the recent paper by Jeff Schwartz in the Journal of Biogeography, in which a complete failure to understand the basics of molecular evolution and systematics is extensively demonstrated.
June 30th, 2009 at 4:01 pm
I wasn’t aware of that, so thanks :)
I just thought it was a rather short post, and related to exactly what I’m working on right now, so it was as good an opportunity to blog on it as any :)
Now I’m debating with myself if I should check that paper out just for fun. I’ve sat at oral exams eight hours and need something else to do right now to relax…