Highly Endangered African Wild Dogs (Lycaon pictus) Lack Variation at the Major Histocompatibility Complex

Abstract

The major histocompatibility complex (MHC) is a set of highly polymorphic genes involved in the immune response. Extensive research on the canid MHC has found moderate-to-high levels of diversity at the DLA-DRB1, DLA-DRA, DLADQA1, and DLA-DQB1 class II loci with frequent transspecific polymorphism among Canis species. In this study, we assessed MHC variation in the more distantly related and highly endangered African wild dog (Lycaon pictus). We screened 168 African wild dogs from Eastern and Southern Africa as well as 200 samples from the European captive population for variation at MHC class II loci. As for all other canids screened to date, we found a single allele at DLA-DRA, which was the same as that found in Canis species. In contrast, we found 17 DLA-DRB1 alleles, one DLA-DQA1 allele, and two DLADQB1 alleles, all of which were unique to African wild dogs. At DLA-DRB1, African wild dogs were found to have comparable numbers of alleles but less overall amino acid variation than other canids. However, the low numbers of alleles at DLA-DQA1 and DLA-DQB1 are surprising, given that in other canids, these loci are also highly variable. Overall, our data suggest that African wild dogs are genetically depauperate at the MHC relative to other canids. These data are indicative of a loss of genetic variation, possibly as a result of population bottlenecks and declines experienced by this species.