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.