Molecular genetic tools for evaluating the consequences of habitat fragmentation

Abstract

Fragmentation and loss of habitat is a serious problem facing the conservation of biodiversity. Habitat fragmentation can lead to reduction in the connectivity between primate populations and ultimately isolation of populations. Decreased levels of gene flow among small populations can lead to decreased genetic variability and concomitantly a reduced ability to adapt to changing environments. Habitat fragmentation may also lead to increased inbreeding, reduced reproductive success, reduction in survival and an increased probability of extinction. Using molecular genetic tools, scientists can measure genetic diversity within and between populations and investigate genetic differentiation between populations of primates living in fragments. Theory predicts a positive correlation between genetic variation and population size and between genetic differentiation and geographic distance among populations. Using genetic data, statistical methods, and computer programs, it is possible to test these predictions and to evaluate the consequences of fragmentation on primates. This chapter reviews the genetic tools available to primatologists interested in evaluating the consequences of habitat fragmentation. Since reduced genetic variation can also potentially lead to increased susceptibility to disease, it is increasingly important to determine what regions of the genome are affected by reduced gene flow and to understand the mechanisms by which genetic diversity changes in association with habitat loss and fragmentation. These are new and important challenges for primate geneticists in the coming decade.