Patterns of microsatellite polymorphism in the range-restricted bonobo (Pan paniscus): considerations for interspecific comparison with chimpanzees (P-troglodytes)

The endangered great ape, Pan paniscus (bonobo) has the smallest range of t he African apes. Virtually nothing is known about the genetic diversity or genetic structure of this species, while substantial amounts of polymorphis m have been reported for the bonobo's widespread congener, the chimpanzee ( P. troglodytes). Given its restricted range, what is the extent of genetic variation in the bonobo relative to the chimpanzee, and is the bonobo genet ically depauperate? To investigate patterns of genetic polymorphism, bonobo s of wild origin were genotyped for 28 microsatellite loci. The mean number of alleles per locus (5.2) and the mean observed heterozygosity (0.52) in bonobos were similar to variation observed in a wild chimpanzee community ( P. t. schweinfurthii). The rarer bonobo is not genetically depauperate and may have genetic diversity comparable to the eastern chimpanzee subspecies. Bonobos have approximately 55% of the allelic diversity and 66% of the obs erved heterozygosity exhibited by all three chimpanzee subspecies sampled a cross equatorial Africa. Resampling techniques were used to quantify the ef fects of sample size differences and number and choice of loci between bono bos and chimpanzees. The examination of these variables underscores their i mportance in accurately interpreting interspecific comparisons of diversity estimates.