Genetic conservation in captive populations and endangered species

Many rare and endangered species require genetic conservation strategies involving an ex situ management phase prior to their reintroduction in nature. Since small populations are likely to lose genetic variation and suffer from inbreeding depression, these strategies are designed in genetic terms to monitor and avoid these effects as short-term goals, and to retain reestablishment or adaptive potential in nature as the long-term goal. Population genetic theory helps us define the concepts of effective population size, inbreeding and population subdivision, and discuss changes in homozygosis, genetic variance, and fitness in small populations. Estimates of several parameters in these models are presented for cheetah Acinonyx jubatus Przewalski's horse Equus przewalskii and Speke's gazelle Gazella spekei. Intermatings among different populations bred in captivity or conserved in natural habitats can be guided by the genetic models of migration, mating systems, and drift. Rates of changes in the level of inbreeding can be monitored to avoid drastic fitness losses, and thereby evolving tolerance of certain amounts of inbreeding. -from Author