MHC-linked and un-linked class I genes in the wallaby

• DOI: 10.1186/1471-2164-10-310
• Publication Date: 2009-07-14T18:14:20Z
• Authors: Hannah V Siddle; Janine E Deakin; Penny Coggill; Elizabeth Hart; Yuanyuan Cheng; Emily SW Wong; Jennifer Harrow; Stephan Beck; Katherine Belov
• Keywords: Antigen processing

Abstract Background MHC class I antigens are encoded by a rapidly evolving gene family comprising classical and non-classical genes that found in all vertebrates involved diverse immune functions. However, there is fundamental difference between the organization of mammals non-mammals. Non-mammals have single responsible for antigen presentation, which linked to processing genes, including TAP. This allows co-evolution advantageous Ia/TAP haplotypes. In contrast, multiple within MHC, separated from III genes. It has been hypothesized separation allowed them duplicate. We investigated this hypothesis characterizing tammar wallaby, model marsupial novel organization, with located 10 other chromosomal locations. Results Sequence analysis 14 BACs containing 15 revealed nine one three I, not but scattered throughout genome. Kangaroo Endogenous Retroviruses (KERVs) were identified flanking un-linked I. The wallaby contains four interspersed Clear orthologs conserved distant lineages. Conclusion demonstrate provide evidence retroviral elements their movement. presence most likely facilitated formation recombination hotspots subsequent diversification moved away eutherian independently, both lineages appear benefited loss linkage increasing number perhaps enabling response wider range pathogens. discovery distantly related species unusual may indicate an important specific function.