Vetsuisse Faculty, Institute of Genetics, University of Bern, Bern, 3001, Switzerland.
ProSpecieRara, Basel, 4052, Switzerland.
Anim Genet. 2020 Dec;51(6):968-972. doi: 10.1111/age.12994. Epub 2020 Aug 17.
Ear morphology is an important determinant of sheep breeds. It includes different variable traits such as ear size and erectness, suggesting a polygenic architecture. Here, we performed a comprehensive genome-wide analysis to identify regions under selection for ear morphology in 515 sheep from 17 breeds fixed for diverse ear phenotypes using 34k SNP genotyping data. GWASs for two ear type traits, size and erectness, revealed a single genome-wide significant association on ovine chromosome 3. The derived marker alleles were enriched in sheep with large and/or floppy ears. The GWAS signal harboured the MSRB3 gene encoding methionine sulphoxide reductase B3, which has already been found to be associated with different ear types in other species. We attempted whole-genome resequencing to identify causal variant(s) within a 1 Mb interval around MSRB3. This experiment excluded major copy number variants in the interval, but failed to identify a compelling candidate causal variant. Fine-mapping suggested that the causal variant for large floppy ears most likely resides in a 175 kb interval downstream of the MSRB3 coding region.
耳朵形态是绵羊品种的一个重要决定因素。它包括不同的可变量特征，如耳朵大小和竖立程度，表明其具有多基因结构。在这里，我们使用 34k SNP 基因分型数据，对来自 17 个品种的 515 只绵羊的耳朵形态进行了全面的全基因组分析，以鉴定选择耳朵形态的区域。对两种耳朵类型性状（大小和竖立程度）的 GWAS 分析揭示了绵羊 3 号染色体上的一个全基因组显著关联。衍生的标记等位基因在具有大耳朵和/或松软耳朵的绵羊中富集。GWAS 信号包含 MSRB3 基因，该基因编码蛋氨酸亚砜还原酶 B3，在其他物种中已发现与不同的耳朵类型有关。我们尝试对 MSRB3 周围 1 Mb 区间内的因果变异进行全基因组重测序。该实验排除了该区间内的主要拷贝数变异，但未能确定有说服力的候选因果变异。精细映射表明，大而松软耳朵的因果变异最有可能位于 MSRB3 编码区域下游的 175kb 区间内。
