Chimpanzees (Pan troglodytes) are of broad interest due to their close evolutionary relationship with humans, complex social systems, and wide distribution across forested areas of Africa. Chimpanzees might be divided into as many as five subspecies. Mitochondrial (mt) DNA sequence analyses indicate these subspecies may be divided into two groups: a western African group (P. t. verus and P. t. vellerosus) and a central/eastern African group (P. t. troglodytes, P. t. schweinfurthii, and P. t. marunguensis). There is an abrupt genetic transition between these groups at the Sanaga River in central Cameroon, and possibly, in western Africa at the Niger River in Nigeria. However, the patterning of genetic variation near the Sanaga and Niger remains largely unknown. The goal of this project is to place chimpanzees from Nigeria and Cameroon into a broader context by generating and comparing genetic data from mtDNA, sex chromosomes and autosomes from chimpanzees originating in Nigeria and Cameroon to those from other regions. These data will be used to (1) test alternative demographic scenarios of chimpanzee genetic history, (2) understand how different population parameters have influenced chimpanzee demographic history and (3) explore how rivers have affected the partitioning of chimpanzee genetic diversity. Studies of intraspecific variation among chimpanzees and other apes have recently blossomed. These studies have tested among complex scenarios of demographic history, which has important implications for understanding the differences in the genetic history of humans and chimpanzees. Previous studies have not included chimpanzees occupying Nigeria and Cameroon despite the putative importance of this region in shaping historical patterns of genetic diversity in this species. This problem prevents more completely understanding the genetic history of this species across Africa. This project will facilitate inferring a demographic history of chimpanzees in the region and may illuminate whether chimpanzees in western Africa have experienced a distinctly different demographic history compared to those chimpanzees in central Africa and eastern Africa. It will also illuminate how the Sanaga and Niger Rivers have influenced the distribution of genetic diversity among chimpanzees. This project will also shed light on the unusual pattern of SIVcpz infection among chimpanzees in Cameroon, which may have important implications for understanding the natural history of SIVcpz infection. The results of this project may also serve as a guide to enhance conservation efforts for critically endangered chimpanzee communities inhabiting Nigeria and Cameroon. All results of this project will be published in peer-reviewed journals. All data will be made publicly available. These data will serve as an important comparative database for geneticists conducting research on humans, chimpanzees and other primates for many years to come. Samples will be shared with colleagues in Africa and in the United States, allowing an international group of scientists to develop independent research projects using the collected samples. This project will also provide important training opportunities for a postdoctoral scholar and university students. The project is structured to ensure effective participation of minority undergraduate students and to introduce them to potential careers in science.
