Insights from noninvasive genetic analysis into the evolutionary dynamics of wild ape populations

Linda Vigilant

Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany

Genetic analysis of wild ape populations can be used to address a variety of questions. One central question is understanding the evolution of primate social systems, which requires knowledge of reproductive patterns and kin relationships within wild populations. Chimpanzees and gorillas live in groups containing multiple adult females and from one to many adult males. We have conducted genetic analyses of members of multiple groups of each species in order to determine paternity of group offspring and quantify relatedness between group members. The factors associated with male reproductive success, particularly dominance rank, will be discussed.
Characterization of the genetic variation present in wild primate populations has almost entirely been limited to loci believed to be unaffected by selection, such as mitochondrial DNA and nuclear microsatellites. While informative, such neutral loci do not exhibit variation associated with a phenotypic effect. The genes of the major histocompatibility complex (MHC) loci play a role in immune response and appear to experience strong diversifying selection. Standard methods for characterization of individual variation at MHC loci are not applicable to the degraded, low concentration DNA obtained from noninvasive samples. We have used direct amplification of a class II MHC locus with subsequent cloning and sequencing to type gorillas from two wild gorilla populations. Preliminary results concerning relative levels of diversity will be presented.