An ancient interlocus recombination increases class II MHC DQA diversity in sheep and other Bovidae. (June 2015)

• Record Type: Journal Article
• Authors: Ballingall, Keith T.; Steele, Philip; Lantier, Isabelle; Cotelli, Matteo; Todd, Helen; Lopez, Guido; Martin, Elena; Lantier, Frederic
• Is Part Of: Animal genetics. Volume 46:Number 3(2015:Jun.)
• Page Start: 333
• Page End: 336
• Publication Date: 2015-06
• Subjects: Animal genetics -- Periodicals; 572.8
• DOI: 10.1111/age.12290
• Languages: English
• ISSNs: 0268-9146

Abstract

<abstract abstract-type="main" id="age12290-abs-0001"> <title>Summary</title> <p>Animals with fully characterised major histocompatibility complex (MHC) regions are often used to explore the molecular interactions that control the induction of adaptive immunity. The ovine MHC includes two <italic>DQA</italic> loci, termed <italic>DQA1</italic> and <italic>DQA2</italic>. However, in a minority of haplotypes the <italic>DQA1</italic> locus appears absent (<italic>DQA1</italic> null) and is replaced by a second locus termed<italic>, DQA2‐like</italic>. This raises a number of questions regarding the origins and function of the <italic>DQA2‐like</italic> sequences. To address this, we have analysed <italic>DQA</italic> diversity associated with 10 MHC haplotypes, including two classified as <italic>DQA1</italic> null. Pair‐wise comparison between full‐length <italic>DQA</italic> transcripts from each haplotype identified unique diversity throughout the <italic>DQA2‐like</italic> sequences. Conserved orthologues of the <italic>DQA2‐like</italic> sequences were identified in cattle and goat, and phylogenetic analysis clustered exons 1 and 2 with <italic>DQA2</italic> whereas the remainder of the sequence clustered with <italic>DQA1</italic>. The <italic>DQA2‐like</italic> allelic lineage appears functional and to have arisen from an ancient interlocus recombination between <italic>DQA1</italic> and <italic>DQA2</italic> loci which predates <italic>Bovidae</italic> speciation.</p> </abstract>