Study affirms chimp-human gene theory

CHICAGO, March 8 (UPI) -- U.S. and Australian scientists say a 30-year-old theory is correct and human and chimpanzee differences aren't due to differences in individual genes.

Researchers from the University of Chicago, Yale University and the Hall Institute in Australia, say they've found evidence supporting the theory proposed in a 1975 paper from Mary-Claire King and Allan Wilson of Berkeley.

That paper documented the 99-percent similarity of genes from humans and chimps and suggested altered gene regulation, rather than changes in coding, might explain how so few genetic changes could produce the wide anatomic and behavioral differences between the species.

"When we looked at gene expression, we found fairly small changes in 65 million years of the macaque, orangutan, and chimpanzee evolution," said the author of the recent study, Yoav Gilad, assistant professor of human genetics at the University of Chicago, "followed by rapid change, along the 5 million years of the human lineage, that was concentrated on these specific groups of genes. This rapid evolution in transcription factors occurred only in humans."

The research is detailed in the March 9 issue of the journal Nature.