Department of Biology, Stanford University, Stanford, California, USA.
Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, México.
Mol Ecol. 2024 Dec;33(23):e16489. doi: 10.1111/mec.16489. Epub 2022 May 27.
Understanding how organisms adapt to changing environments is a core focus of research in evolutionary biology. One common mechanism is adaptive introgression, which has received increasing attention as a potential route to rapid adaptation in populations struggling in the face of ecological change, particularly global climate change. However, hybridization can also result in deleterious genetic interactions that may limit the benefits of adaptive introgression. Here, we used a combination of genome-wide quantitative trait locus mapping and differential gene expression analyses between the swordtail fish species Xiphophorus malinche and X. birchmanni to study the consequences of hybridization on thermotolerance. While these two species are adapted to different thermal environments, we document a complicated architecture of thermotolerance in hybrids. We identify a region of the genome that contributes to reduced thermotolerance in individuals heterozygous for X. malinche and X. birchmanni ancestry, as well as widespread misexpression in hybrids of genes that respond to thermal stress in the parental species, particularly in the circadian clock pathway. We also show that a previously mapped hybrid incompatibility between X. malinche and X. birchmanni contributes to reduced thermotolerance in hybrids. Together, our results highlight the challenges of understanding the impact of hybridization on complex ecological traits and its potential impact on adaptive introgression.
了解生物如何适应不断变化的环境是进化生物学研究的核心关注点。一个常见的机制是适应性渐渗，随着全球气候变化等生态变化的影响，它作为种群快速适应的潜在途径受到越来越多的关注。然而，杂交也可能导致有害的遗传相互作用，从而限制适应性渐渗的好处。在这里，我们使用剑尾鱼物种 Xiphophorus malinche 和 X. birchmanni 之间的全基因组数量性状位点映射和差异基因表达分析的组合来研究杂交对耐热性的影响。虽然这两个物种适应不同的热环境，但我们记录了杂种耐热性的复杂结构。我们确定了一个基因组区域，该区域导致携带 X. malinche 和 X. birchmanni 祖先杂合子的个体耐热性降低，以及在亲本物种对热应激做出反应的基因中广泛的错误表达，特别是在生物钟途径中。我们还表明，先前映射的 X. malinche 和 X. birchmanni 之间的杂交不亲和性导致杂种耐热性降低。总之，我们的结果强调了理解杂交对复杂生态特征的影响及其对适应性渐渗的潜在影响的挑战。
