Human genes take evolutionary turns

Scientists have identified a set of genes that has evolved an extensive pattern of alterations unique to people, at least when compared with corresponding genes in chimpanzees and mice.

Specific molecular adjustments to these genes benefited humans and so were retained through natural selection, says a team led by Michele Cargill of Celera Diagnostics in Alameda, Calif.

The researchers describe their statistical analyses of the chemical makeup of corresponding genes in humans, chimps, and mice in the Dec. 12, 2003 Science. Of particular interest, they say, are the more than 1,500 human genes that contain unique mutations apparently produced through natural selection during our species’ evolution.

These mutations serve a variety of biological functions. One of the affected genes has been implicated in speech development, and 21 others are known to influence ear development. Fine-tuning of our hearing capacity made it possible to understand spoken language, the researchers speculate. Distinctive changes also occurred in human genes that affect the sense of smell.

The new study examined only protein-coding genes. Researchers have yet to examine whether natural selection affected the structure of genes that regulate the activity of other genes.


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Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.