Clarification of genetic terms and their use in the management of captive populations

Some of the concepts, terms, and methods used in the genetic management of captive populations have not been defined precisely in the scientific literature and consequently have been misunderstood and misused. The definitions and interrelationships among gene diversity, effective population size, founder genome equivalents, inbreeding, allelic diversity, mean kinship, and kinship value are presented here. It is important to understand what populations and generations are used as the baselines against which losses of genetic variation are measured. Gene diversity and founder genome equivalents are defined relative to a source population from which founders of the captive population were randomly sampled. Inbreeding and allelic diversity are assessed relative to the founders. The potential gene diversity that would result from an equalization of frequencies of founder alleles retained in the population can never be achieved because, among other limitations, the random process of gene transmission will prevent equalization of allele frequencies even if animals are bred optimally. The gene diversity achievable with the population can be determined by iterative production of hypothetical offspring from the pairs with lowest mean kinship. The long-term objective for offspring production from each animal is also thereby generated. Mean kinships should be recalculated with each real or hypothetical birth and death, because offspring objectives based on current mean kinships might correlate poorly with the optimal long-term offspring objectives. (C) 1995 Wiley-Liss, Inc.