Heterozygosity-fitness correlations and their relevance to studies on inbreeding depression in threatened species

The majority of reported multilocus heterozygosity-fitness correlations (HFCs) are from large, outbred populations, and their relevance to studies on inbreeding depression in threatened populations is often stressed. The results of such HFC studies conducted on outbred populations may be of limited application to threatened population management, however, as bottlenecked populations exhibit increased incidence of inbreeding, increased linkage disequilibrium, reduced genetic diversity and possible effects of historical inbreeding such as purging. These differences may affect both our ability to detect inbreeding depression in threatened species, and our interpretation of the underlying mechanisms for observed heterozygosity-fitness relationships. The study of HFCs in outbred populations is of interest in itself, but the results may not translate directly to threatened populations that have undergone severe bottlenecks.