Genomic regions associated with stature in African Bos taurus
Five candidate regions (2, 4, 8, 9, 12) in the African cohorts harbor nine candidate genes associated with human height identified by GWAS (Gudbjartsson et al. 2008; Soranzo et al. 2009; Okada et al. 2010; Lanktree et al. 2011; Kim et al. 2010; Weedon et al. 2008). Previously, FBP2 and PTCH1 genes underlying region 8 (BTA-8) have been associated with stature in European dairy and beef breeds, respectively (Weedon et al. 2008; Kim et al. 2010; Lanktree et al. 2011; Pryce et al. 2011). In region 12 (BTA-19), the growth hormone genes (GH1, GH2) are strong candidates for dairy production traits (Hayes et al. 2009; Rothammer et al. 2013; Mullen et al. 2010). Moreover, three genes (WDR68, MAP3K3, and LYK5) neighboring growth hormone genes have also been associated with human height in multiple GWAS reports (Gudbjartsson et al. 2008; Soranzo et al. 2009; Lanktree et al. 2011). The remaining three candidate regions, i.e., regions 2, 4, and 9, harbor the stature-associated SPAG17, SCMH1, and CYP19A1 genes, respectively (Weedon et al. 2008; Kim et al. 2010; Okada et al. 2010; Lanktree et al. 2011).
Overall, four of the five candidate regions identified in the African cohorts are novel for their association with bovine stature. This suggests that the strategy of combining CSS and multibreed panels showed utility in the African cohorts also, although the overall proportion of candidate gene regions detected was lower compared to European cohorts. High levels of Bos indicus admixture, smaller sample size, and ascertainment bias of the Illumina BovineSNP50 chip in the African Bos taurus breeds may have impacted the power to detect regions under selection (Randhawa et al. 2014; Decker et al. 2009; Gautier et al. 2010; Gautier and Naves 2011).