Genome-wide scan for signatures of selection in the Brangus cattle genome

CECCO PAULO; ROGBERG MUÑOZ A; BALBI, M.; BONAMY, M.; MUNILLA S; FORNERIS N; PERAL GARCIA P; CANTET R. J. C.; GIOVAMBATTISTA G; FERNANDEZ M E

JOURNAL OF ANIMAL BREEDING AND GENETICS-ZEITSCHRIFT FUR TIERZUCHTUNG UND ZUCHTUNGSBIOLOGIE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2022

0931-2668

Brangus is a composite cattle breed developed with the objective of combining theadvantages of Angus and Zebuine breeds (Brahman, mainly) in tropical climates.The aim of this work was to estimate breed composition both genome-wideandlocally, at the chromosome level, and to uncover genomic regions evidencing positiveselection in the Argentinean Brangus population/nucleus. To do so, we analysedmarker data from 478 animals, including Brangus, Angus and Brahman.Average breed composition was 35.0% ± 9.6% of Brahman, lower than expectedaccording to the theoretical fractions deduced by the usual cross-breedingpracticein this breed. Local ancestry analysis evidenced that breed composition variesbetween chromosomes, ranging from 19.6% for BTA26 to 56.1% for BTA5. Usingapproaches based on allelic frequencies and linkage disequilibrium, genomic regionswith putative selection signatures were identified in several chromosomes(BTA1, BTA5, BTA6 and BTA14). These regions harbour genes involved in horndevelopment, growth, lipid metabolism, reproduction and immune response. Weargue that the overlapping of a chromosome segment originated in one of the parentalbreeds and over-representedin the sample with the location of a signatureof selection constitutes evidence of a selection process that has occurred in thebreed since its take off in the 1950s. In this regard, our results could contribute tothe understanding of the genetic mechanisms involved in cross-bredcattle adaptationand productivity in tropical environments.