Using the Mus musculus hybrid zone to assess covariation and genetic architecture of limb bone lengths

Two subspecies of the house mouse, Mus musculus domesticus and Mus musculus musculus, meet in a narrow contact zone across Europe. Mice in the hybrid zone are highly admixed, representing the full range of mixed ancestry from the two subspecies. Given the distinct morphologies of these subspecies, these natural hybrids can be used for genome-wide association mapping at sufficiently high resolution to directly infer candidate genes. We focus here on limb bone length differences, which is of special interest for understanding the evolution of developmentally correlated traits. We used 172 first-generation descendants of wild-caught mice from the hybrid zone to measure the length of stylopod (humerus / femur), zeugopod (ulna / tibia) and autopod (metacarpal / metatarsal) elements in skeletal CT scans. We find phenotypic covariation between limb elements in the hybrids similar to patterns previously described in M. m. domesticus inbred strains, suggesting that the hybrid genotypes do not in...

小家鼠（Mus musculus）的两个亚种——小家鼠欧洲亚种（Mus musculus domesticus）与小家鼠指名亚种（Mus musculus musculus），在欧洲全境形成狭窄的杂交接触带。该杂交带内的小鼠具有高度的遗传混合背景，涵盖了来自两个亚种的全部谱系混合类型。鉴于这两个亚种具有显著的形态差异，这类自然杂交个体可用于高分辨率全基因组关联定位（genome-wide association mapping），以直接推断候选基因。本研究聚焦于四肢骨骼长度差异，该性状对于理解发育相关性状的演化机制具有重要研究价值。我们使用了172只源自杂交带野生小鼠的第一代后代，通过骨骼CT扫描测量了肢柱段（stylopod，肱骨/股骨）、肢中段（zeugopod，尺骨/胫骨）以及肢远端（autopod，掌骨/跖骨）的骨骼长度。研究发现，杂交个体四肢骨骼间的表型协同变异模式与此前在小家鼠欧洲亚种近交系中报道的结果一致，这表明杂交基因型并未……