One of the major endeavors of biological anthropology is to understand how great apes have adapted to their environment over evolutionary time. Despite great efforts in the past, the underlying molecular mechanisms have remained elusive and empirical demonstrations of selection in natural populations have been difficult. In the era of comparative genomics, however, this question has become truly tractable. Among great apes, orangutans represent a unique model to study the genetic basis of adaptive evolution between and within species, as they show remarkable systematic geographic variation in traits such as brain size, fat storage ability, interbirth-intervals, male developmental arrest and social organization.
Most of these systematic differences in orangutan traits are thought to be at least partially due to habitat differences, in particular temporal and spatial stability of food supply and perhaps also the abundance of large predators, i.e. tigers. Using a population genomics approach, our research aims to identify the genetic signatures of adaptive evolution in orangutans. To disentangle adaptive evolution from non-adaptive processes such as genetic drift, we are also integrating demographic modeling into our selection analyses.
Despite being one of our closest living relatives, relatively little is known about the evolutionary processes that shaped the current genetic makeup of extant orang-utans. We have been and are currently working on several projects that examine the phyolgeographic patterns and population genetics aspects of both species in Borneo and Sumatra.
With our collaborators from both academic and non-governmental organisations, we established the largest currently existing collection of DNA samples from wild orang-utans. These samples are used to examine current and model past patterns of gene flow between populations, assess dispersal patterns, and to aid conservation decisions regarding the re-introduction of rehabilitant orang-utans.