Genetic heterogeneity in five captive specific pathogen-free groups of rhesus macaques.

Gene diversity was used to estimate genetic heterogeneity in the founders of five specific pathogen-free (SPF) colonies of rhesus macaques (Macaca mulatta) and ranged from about 0.20 to 0.32. In the founders of three groups at the California Regional Primate Research Center (CRPRC) that have been minimally managed to maintain genetic heterogeneity, gene diversity was about 0.30, approximately the value for that species, and has declined at the rate of only about 2.5% per generation since 1976. Without intervention, less than half the gene diversity in SPF harem groups will remain after 5 generations whereas gene diversity in multimale SPF groups should decline at less than half that rate. The proportion of gene diversity attributable to average differences among the three groups at the CRPRC, indicating the level of genetic subdivision, was lower than that in the founders of all but one of the SPF colonies and actually declined slightly over a 10-year period. Genetic subdivision in SPF colonies consisting of harem breeding groups was about three times that in colonies consisting of multimale breeding groups. The number of male breeders should be increased and variance in male reproductive success should be reduced in all SPF colonies, especially those containing multimale breeding groups. Genetic heterogeneity can most easily be retained, and genetic subdivision prevented, in each breeding group in all SPF colonies by ensuring gene flow among the breeding groups in each colony. Male breeders who exceed the lowest acceptable level of reproductive success in their colony of origin should also be exchanged among different SPF colonies to maximize the effective population size of the breeding groups in all SPF colonies.