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.

中文翻译：

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绵羊的耳朵类型与MSRB3基因座相关。

耳朵的形态是决定绵羊品种的重要因素。它包括不同的可变性状，例如耳朵大小和勃起，暗示着多基因结构。在这里，我们使用34k SNP基因分型数据进行了全面的全基因组分析，以鉴定来自17个品种的515只绵羊的耳朵形态选择区域，这些绵羊针对不同的耳朵表型进行了固定。具有两个耳朵类型特征（大小和勃起）的GWAS显示出绵羊染色体3上存在一个全基因组范围的显着关联。在大耳朵和/或软耳朵的绵羊中富含衍生标记等位基因。GWAS信号包含MSRB3甲硫氨酸亚砜还原酶B3的编码基因，已经发现与其他物种的不同耳朵类型有关。我们尝试对全基因组进行重新测序，以识别MSRB3附近1 Mb间隔内的因果变异。该实验排除了该间隔中的主要拷贝数变异，但未能确定令人信服的候选因果变异。精细映射表明，大的软盘耳朵的因果变体最有可能位于MSRB3编码区域下游175 kb的间隔内。