Characterization of bovine MHC class II DRB3 diversity in South American Holstein cattle populations

TAKESHIMA S-N; GIOVAMBATTISTA, G.; OKIMOTO N.; MATSUMOTO Y.; ROGBERG MUÑOZ A.; ACOSTA T.J.; ONUMA M.; AIDA Y.

TISSUE ANTIGENS

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015

0001-2815

The bovine major histocompatibility complex (BoLA)-DRB3 class II gene is used as a marker for disease and immunological traits, and its polymorphism has been studied extensively in Holstein cattle from temperate and cold regions. We studied the genetic diversity of the BoLA-DRB3 gene in South American Holstein populations to determine whether tropical populations have diverged from those bred in temperate and cold regions by selection and/or crossbreeding with local native breeds. We specifically studied exon 2 of this gene from 855 South American Holstein individuals by a PCR sequence-based typing method. We found a high degree of gene diversity at the allelic (Na > 20 and He > 0.87) and molecular (π > 0.080) levels, but a low degree of population structure (FST = 0.009215). A principal components analysis and tree showed that the Bolivian subtropical population had the largest genetic divergence compared with Holsteins bred in temperate or cold regions, and that this population was closely related to Bolivian Creole cattle. Our results suggest that Holstein genetic divergence can be explained by selection and/or gene introgression from local germplasms. This is the first examination of BoLA-DRB3 in Holsteins adapted to tropical environments; and contribute on an ongoing effort to catalog bovine MHC allele frequencies by breed and location.