Speciation, a process whereby a new evolutionarily independent entity arises, underlies much of the biological diversity seen today. For this reason, it has been the focus of much theoretical work leading to many models of how new species arise and many, often controversial definitions of what a species is. Despite this work, few empirical studies of primates have shed light on the dynamics of speciation. The researchers propose to examine in detail two putative species of cercopithecine monkey and their hybrids, in order to gain a clearer understanding of the genetic consequences of geographic separation and subsequent intergradation. The two species are members of the macaque complex, Macaca maurus and M. tonkeana, on the Indonesian island of Sulawesi. Genetic material will be collected from several hundred individuals within the range of each species and across the intervening hybrid zone. Using automated DNA sequencing technology, the mitochondrial and nuclear genomes will be surveyed for informative markers that reveal the direction and rate of gene flow across the hybrid zone, the relative contribution of males and females of each species to this hybridization process, and the genetic effects of hybridization on the long term evolutionary integrity of each species. Female contributions will be tracked using mtDNA markers, while male mediated gene flow will be reconstructed using nDNA microsatellites. This study will shed light on the process of species formation among higher primates, factors leading to its subsequent breakdown, and possibly why there are so many species of macaque monkeys on Sulawesi.
