The impact of assumptions about founder relationships on the effectiveness of captive breeding strategies

Abstract

Many breeding programs managed by zoos and aquariums employ strategies that minimize mean kinship as a way of retaining genetic diversity (MK strategies). MK strategies depend on accurate and complete pedigrees, but population founders are generally assumed to be unrelated and not inbred. This assumption was historically necessitated by the unavailability of data on founder relationships, but with DNA techniques it is sometimes now possible to estimate those relationships. We used computer simulations to investigate the impact of founder assumptions on the effectiveness of MK strategies. Individuals with known pedigrees were managed in groups of 10, 30, and 100 founders at two different rates of reproduction and two different degrees of founder relationship. The impact of assuming founders were unrelated was quantified by calculating the differences in gene diversity and inbreeding that were observed between simulations that used known relationships and simulations that assumed founders were unrelated. Results indicated that utilizing known relationships retained 0–2% more gene diversity over ten generations than assuming founders were unrelated, with specific results dependent on the conditions of a given scenario. Similar results were observed for inbreeding, with long-term levels of inbreeding being 0–2% lower when relationships were known. There were higher benefits to knowing founder relationships as reproductive rate increased, as well as when full-siblings were included in small groups of founders. Overall, however, long-term benefits gained from knowing founder relationships were generally small. Therefore, MK strategies probably often produce near optimal results when standard founder assumptions are made.