Identification of a major locus interacting with MC1R and modifying black coat color in an F2 Nellore-Angus population

作者：Lauren L Hulsman Hanna, James O. Sanders, David G. Riley, Colette A. Abbey, C. A. Gill · 发表于：Genetics Selection Evolution · 年份：2014 · DOI：10.1186/1297-9686-46-4 · 被引用次数：37 · 研究领域：melanin and skin pigmentation、Genetic Mapping and Diversity in Plants and Animals、Plant Gene Expression Analysis

BACKGROUND: In cattle, base color is assumed to depend on the enzymatic activity specified by the MC1R locus, i.e. the extension locus, with alleles coding for black (E(D)), red (e), and wild-type (E+). In most mammals, these alleles are presumed to follow the dominance model of E(D) > E+ > e, although exceptions are found. In Bos indicus x Bos taurus F2 cattle, some E(D)E+ heterozygotes are discordant with the dominance series for MC1R and display various degrees of red pigmentation on an otherwise predicted black background. The objective of this study was to identify loci that modify black coat color in these individuals. RESULTS: Reddening was classified with a subjective scoring system. Interval analyses identified chromosome-wide suggestive (P < 0.05) and significant (P < 0.01) QTL on bovine chromosomes (BTA) 4 and 5, although these were not confirmed using single-marker association or Bayesian methods. Evidence of a major locus (F = 114.61) that affects reddening was detected between 60 and 73 Mb on BTA 6 (Btau4.0 build), and at 72 Mb by single-marker association and Bayesian methods. The posterior mean of the genetic variance for this region accounted for 43.75% of the genetic variation in reddening. This region coincided with a cluster of tyrosine kinase receptor genes (PDGFRA, KIT and KDR). Fitting SNP haplotypes for a 1 Mb interval that contained all three genes and centered on KIT accounted for the majority of the variation attributed to this major locus, which su...