Managing Genetic Diversity, Fitness and Adaptation of Farm Animal Genetic Resources

In this review, we first analyse the objectives to consider in preserving diversity, fitness and adaptability of farm animal genetic resources (AnGR), given the links between genetic diversity and fitness-adaptedness (FA) traits. Ways to measure diversity are then presented, and tools available for managing genetic diversity within given economic constraints are described, under a theoretical framework proposed by Martin Weitzman. The emphasis is on molecular diversity and the exploitation of genetic marker information for use in conservation management of AnGR, through the use of a diversity function which may be applied either to gene diversity (based on allele frequencies) or to allelic diversity (based on allele counts). The question is raised of the possible relationships between molecular diversity of AnGR and FA traits. Methods for investigating those relationships based on within-breed heterozygosity or between-breed molecular divergence are reviewed. The concepts are illustrated on data from a European study of pig diversity.