Major histocompatibility complex genes map to two chromosomes in an evolutionarily ancient reptile, the tuatara sphenodon punctatus

摘要: Major histocompatibility complex (MHC) genes are a central component of the vertebrate immune system and usually exist in single genomic region. However, considerable differences MHC organization size between different lineages. Reptiles occupy key evolutionary position for understanding how variation structure evolved vertebrates, but information on region reptiles is limited. In this study, we investigate cytogenetic location tuatara (Sphenodon punctatus), sole extant representative early-diverging reptilian order Rhynchocephalia. Sequencing mapping 12 clones containing class I II from bacterial artificial chromosome library indicated that core located 13q. duplication translocation outside was evident, because additional were 4p. We found total seven sequences 11 β sequences, with evidence pseudogenization within lineage. The characterized by high repeat content low gene density compared other species no antigen processing or framework gene-containing clones. Our findings indicate substantial mammalian avian MHCs highlight dynamic nature MHC. Further sequencing annotation reptile will determine if nonavian general.