The geographic apportionment of mitochondrial genetic diversity in east African chimpanzees, Pan troglodytes schweinfurthii

This study is a geographically systematic genetic survey of the easternmostsubspecies of chimpanzee, Pan troglodytes schweinfurthii. DNA wasnoninvasively collected in the form of shed hair from chimpanzees of knownorigin in Uganda, Rwanda, Tanzania, and Zaire. Two hundred sixty-two DNAsequences from hypervariable region 1 of which of the mitochondrial controlregion were generated. Eastern chimpanzees display levels of mitochondrialgenetic variation which are low and which are similar to levels observed inhumans (Homo sapiens). Also like humans, between 80% and 90% of the geneticvariability within the eastern chimpanzees is apportioned withinpopulations. Spatial autocorrelation analysis shows that genetic similaritybetween eastern chimpanzees decreases clinically with distance, in apattern remarkably similar to one seen for humans separated by equivalentgeographic distances. Eastern chimpanzee mismatch distributions (frequencydistributions of pairwise genetic differences between individuals) aresimilar in shape to those for humans, implying similar population historiesof recent demographic expansion. The overall pattern of genetic variabilityin eastern chimpanzees is consistent with the hypothesis that the subjecthas responded demographically to paleoclimatically driven changes in thedistribution of eastern African forests during the recent Pleistocene.