MHC Class II variability in bare-nosed wombats (Vombatus ursinus)

Abstract

Studies of gene diversity are used to investigate population dynamics, including immunological fitness. Aside from the selection of an appropriate gene target, an important factor that underpins these studies is the ability to recover viable DNA samples from native animals that are protected, threatened or difficult to sample or locate such as the bare-nosed wombat (Vombatus ursinus). In this study, we used genomic DNA extracted from muscle tissue samples and also identified the optimal method to extract DNA from fresh wombat scat samples to enable further analyses to be performed using non-invasive techniques. The DNA was probed via the polymerase chain reaction using previously targeted marsupial Major Histocompatibility Complex (MHC) gene primers. These genes are highly variable and associated with binding and presentation of pathogens in the immune system. Twenty-three unique MHC Class II DAB V. ursinus gene sequences were translated to 21 unique predicted peptide sequences from 34 individual tissue or scat samples. Vombatus ursinus MHC Class II DAB gene and peptide sequences were most similar to other marsupial DNA and peptide sequences. Further analysis also indicated the likelihood of MHC Class II DAB family membership through motif identification. Additional sampling is required to assess the full level of diversity of MHC Class II DAB genes among V. ursinus populations; however, this study is the first to identify MHC genes in a wombat and will advance immunological and disease studies of the species.