Genome-wide association study for growth traits in Blanco Orejinegro and Romosinuano cattle

Abstract Growth traits are economically important characteristics for the genetic improvement of local cattle breeds. Genome-wide association studies (GWAS) provide valuable information to enhance the understanding on the genetics of complex traits. The aim of this study was to perform a GWAS to identify genomic regions and genes associated to birth weight, weaning weight adjusted for 240 days, 16-months and 24-months weight in Romosinuano (ROMO) and Blanco Orejinegro (BON) cattle. A single-step genomic-BLUP was implemented using 596 BON and 569 ROMO individuals that were genotyped with an Illumina BovineSNP50 BeadChip. There were 25 regions of interest identified on different sets of chromosomes depending on the breed, with few of them simultaneously associated with two or more growth traits and some were common to both breeds. A total of 173 annotations were found during the gene mapping, with 50 of them being potential candidate genes with known growth-related functions in cattle and other species. On BTA14, a region at 24 – 27 MB where important candidate genes such as LYPLA1, XKR4, TMEM68 and PLAG1 are located, was associated with several growth traits. Another region of interest at 0.40-0.77 MB of BTA23 was identified in both breeds, containing KHDRBS2 as a potential candidate gene influencing body weight. Future studies targeting these areas could provide more knowledge to uncover the genetic architecture underlying growth traits in BON and ROMO cattle. The genomic regions and genes identified in this study could be used to improve the prediction of genetic merit for growth traits in this creole cattle breeds.