Effect of outbreeding on weight and growth rate of captive infant rhesus macaques

Abstract

AbstractThe introduction of unrelated conspecifics into captive groups of primate species is desirable to inhibit inbreeding. However, for many species, such groups increasingly represent highly inbred isolate populations that are analogous to regionally isolated populations of the same species among whom the effects of outcrossing on fitness are unknown.A study of potentially adverse effects of cross‐breeding between regionally isolated populations of rhesus macaques was conducted to assess the maximum advantage or disadvantage to be expected for cross‐breeding such populations of other cercopithecoid primates. For this purpose, the infant weights and rates of growth of hybrid Chinese/Indian rhesus macaques were compared to those of their nonhybrid Indian peers and to those of consanguineously inbred Indian rhesus macaques from several other captive breeding groups.Neither adverse nor advantageous effects of such hybridization were detected, suggesting that outcrossing between isolates of other cercopithecoid primates with a similar social structure and mating pattern should not affect the fitness of resulting offspring. Since levels of inbreeding are roughly inversely proportional to levels of genetic diversity within populations, such outcrossing should be intensified by zoos and other captive breeding centers to ensure the continued survival of captive species, especially those that are endangered or otherwise irreplaceable.