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By Michael White | June 18th 2009 01:28 PM | 3 comments | Print | E-mail | Track Comments
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About Michael White

Welcome to Adaptive Complexity, where I write about genomics, systems biology, evolution, and the connection between science and literature, government, and society.

I'm a biochemist


... Full Bio

I have a hard time believing this is for real:
Researchers from the University of Pittsburgh and the Buffalo Museum of Science say we've been making a mistake using DNA to contend that humans are most closely related to chimpanzees.  The fossil record says otherwise, they report in the Journal of Biogeography.

Jeffrey H. Schwartz, professor of anthropology in Pitt's School of Arts and Sciences and president of the World Academy of Art and Science, and John Grehan, director of science at the Buffalo Museum, conducted an analysis of the physical features of living and fossil apes that suggested humans, orangutans, and early apes belong to a group separate from chimpanzees and gorillas.

We fought this argument a long time ago, and DNA won.  How? Read on:

Schwartz and Grehan scrutinized the hundreds of physical characteristics often cited as evidence of evolutionary relationships among humans and other great apes—chimps, gorillas, and orangutans—and selected 63 that could be verified as unique within this group (i.e., they do not appear in other primates). Of these features, the analysis found that humans shared 28 unique physical characteristics with orangutans, compared to only two features with chimpanzees, seven with gorillas, and seven with all three apes (chimpanzees, gorillas, and orangutans). Gorillas and chimpanzees shared 11 unique characteristics.

Compared to the 100 or so informative characteristics that these guys used, the DNA-based phylogeny uses thousands of characteristics, and much less subjective ones at that (fossils are much harder to read than DNA). The DNA evidence for the human-chimp-gorilla-orangutan phylogeny is unambiguous - there is absolutely no other remotely plausible scenario that would be consistent with what we see in the genomes of the great apes.

Molecular data is not always great when it comes to the timing of events. Also, early molecular studies, which used only a few genes to determine evolutionary relationships, could be ambiguous. But when you have whole or even partial genomes, DNA evidence can't be beat.







Comments

Hank's picture
It's an interesting talking point more than anything.  We'll see what sort of reaction this gets.   I won't start calling myself a dental hominoid just yet.
The researchers acknowledge, however, that early human and ape fossils are largely found in Africa, whereas modern orangutans are found in Southeast Asia. To account for the separation, they propose that the last common human-orangutan ancestor migrated between Africa, Europe, and Asia at some point that ended at least 12 million to 13 million years ago. 

Bertrand Russell would have a field day with that sort of science.


adaptivecomplexity's picture
It's an interesting talking point more than anything.

I think it also demonstrates that some paleontologists are still living in the pre-genome dark ages.  The molecular guys need a new slogan: "Billions of base pairs can't be wrong!"

We should be happy DNA was discovered. If not, we would continue this kind of pseudo science. Using just the naked eye is much like Sherlock Holmes acting as a researcher.

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