Li M-H, Tiirikka T, Kantanen J
1] Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland [2] Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Biotechnology and Food Research, MTT Agrifood Research Finland, Jokioinen, Finland.
Heredity (Edinb). 2014 Feb;112(2):122-31. doi: 10.1038/hdy.2013.83. Epub 2013 Sep 11.
In sheep, coat colour (and pattern) is one of the important traits of great biological, economic and social importance. However, the genetics of sheep coat colour has not yet been fully clarified. We conducted a genome-wide association study of sheep coat colours by genotyping 47 303 single-nucleotide polymorphisms (SNPs) in the Finnsheep population in Finland. We identified 35 SNPs associated with all the coat colours studied, which cover genomic regions encompassing three known pigmentation genes (TYRP1, ASIP and MITF) in sheep. Eighteen of these associations were confirmed in further tests between white versus non-white individuals, but none of the 35 associations were significant in the analysis of only non-white colours. Across the tests, the s66432.1 in ASIP showed significant association (P=4.2 × 10(-11) for all the colours; P=2.3 × 10(-11) for white versus non-white colours) with the variation in coat colours and strong linkage disequilibrium with other significant variants surrounding the ASIP gene. The signals detected around the ASIP gene were explained by differences in white versus non-white alleles. Further, a genome scan for selection for white coat pigmentation identified a strong and striking selection signal spanning ASIP. Our study identified the main candidate gene for the coat colour variation between white and non-white as ASIP, an autosomal gene that has been directly implicated in the pathway regulating melanogenesis. Together with ASIP, the two other newly identified genes (TYRP1 and MITF) in the Finnsheep, bordering associated SNPs, represent a new resource for enriching sheep coat-colour genetics and breeding.
在绵羊中，毛色（及图案）是具有重要生物学、经济和社会意义的重要性状之一。然而，绵羊毛色的遗传学尚未完全阐明。我们通过对芬兰芬兰羊群体中的47303个单核苷酸多态性（SNP）进行基因分型，开展了一项绵羊毛色的全基因组关联研究。我们鉴定出35个与所有研究毛色相关的SNP，它们覆盖的基因组区域包含绵羊中三个已知的色素沉着基因（TYRP1、ASIP和MITF）。其中18个关联在白色与非白色个体之间的进一步测试中得到证实，但在仅对非白色毛色的分析中，这35个关联均不显著。在所有测试中，ASIP中的s66432.1与毛色变异显示出显著关联（所有毛色的P = 4.2×10⁻¹¹；白色与非白色毛色的P = 2.3×10⁻¹¹），并且与ASIP基因周围的其他显著变异存在强连锁不平衡。在ASIP基因周围检测到的信号可由白色与非白色等位基因的差异来解释。此外，对白色被毛色素沉着选择的全基因组扫描鉴定出一个跨越ASIP的强烈且显著的选择信号。我们的研究确定白色与非白色毛色变异的主要候选基因为ASIP，这是一个常染色体基因，已直接参与调节黑色素生成的途径。与ASIP一起，芬兰羊中另外两个新鉴定出的基因（TYRP1和MITF），与相关SNP相邻，代表了丰富绵羊毛色遗传学和育种的新资源。
