Robles Nemo V, Moran Benjamin M, Rodríguez-Barrera María José, Jofre Gaston I, Gunn Theresa, Iverson Erik N K, Beskid Sofia, Baczenas J J, Sedghifar Alisa, Andolfatto Peter, Powell Daniel L, Brandvain Yaniv, Havird Justin C, Rosenthal Gil G, Schumer Molly
Department of Biology, Stanford University.
Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C.
bioRxiv. 2025 Jun 23:2025.01.30.635158. doi: 10.1101/2025.01.30.635158.
How barriers to gene flow arise between closely related species is one of the oldest questions in evolutionary biology. Classic models in evolutionary biology predict that negative epistatic interactions between variants in the genomes of diverged lineages, known as hybrid incompatibilities, will reduce viability or fertility in hybrids. The genetic architecture of these interactions and the evolutionary paths through which they arise have profound implications for the efficacy of hybrid incompatibilities as barriers to gene flow between species. While these questions have been studied using theoretical approaches for several decades, only recently has it become possible to genetically map larger numbers of hybrid incompatibilities. Here, we use admixture mapping in natural hybrid populations of swordtail fish () to identify hybrid incompatibilities involving genetic interactions between the mitochondrial and nuclear genomes. We find that at least nine regions of the genome are involved in mitonuclear incompatibilities. These incompatibilities involve interactions between the nuclear genome and the mitochondria, the mitochondria, or both. Moreover, they vary in the strength of selection they experience, and the degree to which they limit gene flow in natural hybrid populations. Our results build a deeper understanding of the complex architecture of selection against incompatibilities in naturally hybridizing species and highlight an important role of mitonuclear interactions in the evolution of reproductive barriers between closely related species.
在亲缘关系密切的物种之间，基因流动的障碍是如何产生的，这是进化生物学中最古老的问题之一。进化生物学中的经典模型预测，分化谱系基因组中的变异之间的负上位性相互作用，即所谓的杂种不相容性，会降低杂种的活力或育性。这些相互作用的遗传结构以及它们产生的进化路径，对于杂种不相容性作为物种间基因流动障碍的效力具有深远影响。虽然这些问题已经用理论方法研究了几十年，但直到最近才有可能对大量杂种不相容性进行遗传定位。在这里，我们利用剑尾鱼自然杂交种群中的混合映射来识别涉及线粒体和核基因组之间遗传相互作用的杂种不相容性。我们发现，基因组中至少有九个区域参与了线粒体核不相容性。这些不相容性涉及核基因组与线粒体、线粒体或两者之间的相互作用。此外，它们所经历的选择强度以及它们在自然杂交种群中限制基因流动的程度各不相同。我们的研究结果使人们对自然杂交物种中针对不相容性的选择的复杂结构有了更深入的理解，并突出了线粒体核相互作用在亲缘关系密切的物种之间生殖隔离进化中的重要作用。
