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An ancient interlocus recombination increases class II MHC DQA diversity in sheep and other B ovidae
Author(s) -
Ballingall Keith T.,
Steele Philip,
Lantier Isabelle,
Cotelli Matteo,
Todd Helen,
Lopez Guido,
Martin Elena,
Lantier Frederic
Publication year - 2015
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1111/age.12290
Subject(s) - biology , haplotype , genetics , locus (genetics) , bovidae , major histocompatibility complex , evolutionary biology , allele , gene , zoology
Summary 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 DQA loci, termed DQA 1 and DQA 2 . However, in a minority of haplotypes the DQA 1 locus appears absent ( DQA 1 null) and is replaced by a second locus termed , DQA 2‐like . This raises a number of questions regarding the origins and function of the DQA 2‐like sequences. To address this, we have analysed DQA diversity associated with 10 MHC haplotypes, including two classified as DQA 1 null. Pair‐wise comparison between full‐length DQA transcripts from each haplotype identified unique diversity throughout the DQA 2‐like sequences. Conserved orthologues of the DQA 2‐like sequences were identified in cattle and goat, and phylogenetic analysis clustered exons 1 and 2 with DQA 2 whereas the remainder of the sequence clustered with DQA 1 . The DQA 2‐like allelic lineage appears functional and to have arisen from an ancient interlocus recombination between DQA 1 and DQA 2 loci which predates Bovidae speciation.