The identification of a putative mutation for SLICK hair coat in Senepol cattle

Abstract Text: The slick hair coat (SLICK) is a dominantly inherited trait typically associated with tropically adapted, Criollo-derived cattle breeds.  The trait is of interest relative to climate change, due to its association with improved thermo-tolerance and subsequent increased productivity.  The goal of this work was to identify the mutation underlying the SLICK locus, which was previously mapped to a 4 cM region on chromosome (Chr) 20.  To refine this map position, BovineHD genotypes were generated from a sampling (N=195 animals) of Senepol, Carora, Romosinuano, three additional slick-haired cross-bred lineages and a group of non-slick ancestral breeds. Genome-wide association analysis narrowed the SLICK locus to a 0.8Mb (37.7-38.5 Mbp UMD 3.1) consensus region, which contains SKP2 and SPEF2 as possible candidate genes.  Three specific haplotype patterns were identified in slick individuals, all with zero frequency in non-slick individuals.  In attempt to identify candidate causative mutations in this region, whole genome re-sequencing was completed for one Romosinuano and five Senepol animals.  SNP discovery and annotation analyses revealed a putative causative polymorphism within prolactin receptor (PRLR), which would truncate an encoded domain involved in JAK/STAT5 signaling.  Validation testing of this SNP and 37 others was done across a DNA panel (N=466) that included representation from five SLICK and seven non-SLICK breeds.  The results strongly suggest the frameshift mutation in PRLRis the causative mutation underlying SLICK in Senepol and some Romosinuano cattle.  However, no associations between this SNP and SLICK animals from Limonero and Carora breeds were found. This information along with accompanying population structure information supports potentially two independent SLICK mutations, one common to Senepol and Romosinuano and another in Limonero and Carora.

Keywords: slick hair coat, cattle, prolactin receptor