Male genitalia are among the most phenotypically diverse morphological traits, and sexual selection is widely accepted as being responsible for their evolutionary divergence. Studies of house mice suggest that the shape of the baculum (penis bone) affects male reproductive fitness and experimentally imposed postmating sexual selection has been shown to drive divergence in baculum shape across generations. Much less is known of the morphology of female genitalia and its coevolution with male genitalia. In light of this, we used a paternal half‐sibling design to explore patterns of additive genetic variation and covariation underlying baculum shape and female vaginal tract size in house mice (Mus musculus domesticus). We applied a landmark‐based morphometrics approach to measure baculum size and shape in males and the length of the vaginal tract and width of the cervix in females. Our results reveal significant additive genetic variation in house mouse baculum morphology and cervix width, as well as evidence for genetic covariation between male and female genital measures. Our data thereby provide novel insight into the potential for the coevolutionary divergence of male and female genital traits in a mammal.

中文翻译：

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哺乳动物雄性和雌性生殖器的共同进化：定量遗传洞察

男性生殖器是表型最多样化的形态特征之一，性选择被广泛认为是导致它们进化分歧的原因。对家鼠的研究表明，阴茎骨（阴茎骨）的形状会影响雄性生殖健康，并且实验性强加的交配后性选择已被证明会导致阴茎骨形状的代际差异。人们对女性生殖器的形态及其与男性生殖器的共同进化知之甚少。有鉴于此，我们使用父系半同胞设计来探索家鼠（Mus musculusdomesticus）中生殖器形状和雌性阴道大小的附加遗传变异和协变模式。我们应用了基于地标的形态测量学方法来测量男性的生殖器大小和形状以及女性的阴道长度和子宫颈宽度。我们的研究结果揭示了家鼠生殖器形态和子宫颈宽度的显着累加遗传变异，以及雄性和雌性生殖器测量之间遗传协变的证据。因此，我们的数据提供了对哺乳动物雄性和雌性生殖器特征共同进化差异潜力的新见解。