Chimp hairs yield genetic fallout.

Strands of hair routinely shed by chimpanzees contain genetic information that can illuminate the animals' evolution and social behavior, a scientific team reports in the Aug. 26 SCIENCE. In fact, DNA gleaned from chimp hairs suggests that a third species of these African primates may exist, in addition to the two generally accepted chimp species.

Evolutionary reconstructions of chimps and the 6- to 8-million-year-old ancestor they share with humans "will have to allow for the previously underappreciated [genetic] variation within chimpanzees," assert Phillip A. Morin, a biologist at the University of California, Davis, and his colleagues.

The researchers collected chimp hair from 20 locations in central and western Africa, including the Tanzanian site where Jane Goodall has studied chimp behavior for 30 years. Goodall participated in the new study.

A chimp subspecies living in western African may form a species distinct from common chimps (Pan troglodytes) and pygmy chimps (P. paniscus), Morin's team asserts. They base this conclusion on the extent of differences between these groups in mitochondrial DNA, which is inherited only from the mother. The proposed third species. P. verus, emerged about 1.6 million years ago, the researchers estimate.

Analysis of DNA from the nuclei of hair cells allowed the researchers to trace the genealogy of chimps at the site where Goodall has worked. Males show a much closer genetic relationship to each other than do females, they hold; most males are half-brothers. DNA tests identified the fathers of only two male chimps because many older fathers died in a viral epidemic during the late 1980s.

These findings support the theory that, since female chimps often leave their native social group to find mates in other groups, males in a group are more closely related than females. Close genetic links among male chimps may have helped to foster their high levels of cooperation in pursuit of status and power, the investigators suggest.