Conservation Biology: Genetic Approaches

In the wild, populations that once were large and widespread are increasingly being reduced to small and fragmented isolates due to human activities. Habitat loss and fragmentation trigger processes that further threaten populations. Small populations often face greater demographic and genetic risks relative to large populations. When populations become fragmented and small, the genetic diversity of a population may be greatly affected. Conservation geneticists focus on the impact of such severe reductions, called bottlenecks, on endangered species.

When a bottleneck occurs, there is an increased chance of breeding among close relatives. This is termed inbreeding, and it may result in a reduction in fitness due to the expression of deleterious genes, in a process known as inbreeding depression. Inbreeding and the loss of genetic variation in small populations can lead to a genetically reduced or homogeneous population that is more sensitive to diseases and to the effects of habitat alteration. The interaction between genetic and demographic declines has been termed "extinction vortex." We include below several real examples of the use of genetics in conservation biology.