Genomic conflicts may play a central role in the evolution of reproductive barriers. Theory predicts that early-onset hybrid inviability may stem from conflict between parents for resource allocation to offspring. Here, we describe : a group of cryptic species within the species complex that are largely reproductively isolated by hybrid seed inviability (HSI). HSI between and is common and strong, but populations of vary in the magnitude and directionality of HSI with . Patterns of HSI between and as well as within , conform to the predictions of parental conflict: first, reciprocal F1s exhibit size differences and parent-of-origin-specific endosperm defects; second, the extent of asymmetry between reciprocal F1 seed size is correlated with asymmetry in HSI; and third, inferred differences in the extent of conflict predict the extent of HSI between populations. We also find that HSI is rapidly evolving, as populations that exhibit the most HSI are each others’ closest relative. Lastly, although all populations appear largely outcrossing, we find that the differences in the inferred strength of conflict scale positively with π, suggesting that demographic or life history factors other than transitions to self-fertilization may influence the rate of parental-conflict-driven evolution. Overall, these patterns suggest the rapid evolution of parent-of-origin-specific resource allocation alleles coincident with HSI within and between and Parental conflict may therefore be an important evolutionary driver of reproductive isolation.

中文翻译：

---

混合种子不活力模式在酸酸浆菌中。复杂揭示了父母冲突在生殖隔离中的潜在作用

基因组冲突可能在生殖障碍的演变中发挥核心作用。理论预测，早发的杂交不可行可能源于父母之间为后代分配资源的冲突。在这里，我们描述了：物种复合体中的一组神秘物种，它们在很大程度上通过杂交种子不存活性（HSI）而被生殖隔离。介于 和 之间的 HSI 常见且较强，但人口中 HSI 的大小和方向性随 变化。之间和内部的 HSI 模式符合亲本冲突的预测：首先，相互的 F1 表现出大小差异和亲本来源特异性胚乳缺陷；其次，F1 种子大小倒数之间的不对称程度与 HSI 的不对称程度相关；第三，推断冲突程度的差异可以预测人群之间 HSI 的程度。我们还发现 HSI 正在迅速演变，因为表现出最多 HSI 的人群彼此之间是最亲近的亲戚。最后，虽然所有种群都出现很大程度上异型杂交，但我们发现推断的冲突强度的差异与 π 成正比，这表明除了向自体受精过渡之外的人口或生活史因素可能会影响亲本冲突驱动的进化速率。总体而言，这些模式表明，亲本特异性资源分配等位基因的快速进化与 HSI 内部和之间的 HSI 一致，因此亲本冲突可能是生殖隔离的重要进化驱动因素。