Data from: Mechanical incompatibility caused by modifications of multiple male genital structures using genomic introgression in Drosophila

Mechanical incompatibility of male and female genitalia is common in
animals with internal fertilization. However, our knowledge regarding the
precise mechanisms is limited. One key question regards the susceptibility
of the match between male and female genitalia to morphological
modification. To address this issue, we generated six different
second-chromosome introgression lines possessing partially Drosophila
mauritiana-like genital morphology in multiple structures in D. simulans
background. Three of the six introgression males showed elevated mobility
at some stages during copulation with D. simulans females; this was
assumed to be an indication of genital mismatch. Notably, one of the
introgression males with D. mauritiana-like enlarged anal plates showed
occasional leakage of adhesive ejaculate on the body surface when mated
with pure D. simulans females, suggesting apparent structural
incompatibility in genital coupling. These observations suggested that
both sexual and natural selection shape the anal plate morphology,
highlighting the role of this structure as an important component of
mechanical isolation. Partial replacement (introgression) by a sibling
species genome can induce perturbations in genital coupling mechanics,
suggesting that genital compatibility can be susceptible to subtle genomic
changes at the early stages of divergence in these species.

具有体内受精方式的动物中，雌雄生殖器的机械不兼容性普遍存在。然而，目前学界对其精确作用机制的认知仍较为有限。其中一个核心科学问题是：雌雄生殖器的匹配模式是否易受形态改造的影响。
为解答这一问题，本研究构建了6个不同的第二染色体渐渗系（introgression lines），这些品系在拟果蝇（Drosophila simulans）的遗传背景下，多个生殖器结构呈现出部分毛里求斯果蝇（Drosophila mauritiana）式的形态特征。
6个渐渗系雄果蝇中有3个，在与拟果蝇雌果蝇交配的部分阶段表现出运动能力增强的现象，这被认为是生殖器匹配度不足的指征。值得注意的是，其中1个带有毛里求斯果蝇式扩大肛板（anal plate）的渐渗系雄果蝇，在与纯种拟果蝇雌果蝇交配时，偶尔会出现粘性射精产物渗漏至体表的情况，这表明生殖器接合（genital coupling）过程中存在显著的结构不兼容性。
上述观察结果提示，性选择与自然选择共同塑造了肛板的形态，凸显了该结构作为机械隔离（mechanical isolation）重要组成部分的作用。通过近缘物种基因组进行的部分替换（渐渗）可扰乱生殖器接合的力学机制，这表明在这些物种分化的早期阶段，生殖器兼容性易受细微基因组变化的影响。