Pure species discriminate against hybrids in the Drosophila melanogaster species subgroup

Introgression, the exchange of alleles between species, is a common event in nature. This transfer of alleles between species must happen through fertile hybrids. Characterizing the traits that cause defects in hybrids illuminate how and when gene flow is expected to occur. Inviability and sterility are extreme examples of fitness reductions but are not the only type of defects in hybrids. Some traits specific to hybrids are more subtle but are important to determine their fitness. In this report, we study whether F1 hybrids between two species pairs of Drosophila are as attractive as the parental species. We find that in both species pairs, the sexual attractiveness of the F1 hybrids is reduced and that pure species discriminate strongly against them. We also find that the cuticular hydrocarbon (CHC) profile of the females hybrids is intermediate between the parental species. Perfuming experiments show that modifying the CHC profile of the female hybrids to resemble pure species improv...

渐渗（Introgression）指物种间等位基因的交换，是自然界中普遍存在的演化事件。此类跨物种的等位基因转移必须借助可育杂种完成。解析引发杂种发育缺陷的性状，可阐明基因流发生的具体方式与时机。杂种的不可育性与不育性属于适合度降低的极端案例，但并非杂种缺陷的唯一类型。部分杂种特有的性状虽更为细微，却对其适合度具有关键影响。本研究旨在探究两个果蝇（Drosophila）物种对的F1杂种是否与亲本物种具备同等的性吸引力。研究结果显示，在两个物种对中，F1杂种的性吸引力均出现显著下降，且纯种亲本物种对杂种存在强烈的识别排斥行为。此外，雌性杂种的表皮碳氢化合物（cuticular hydrocarbon, CHC）谱型介于两个亲本物种之间。气味修饰实验表明，将雌性杂种的表皮碳氢化合物谱型修饰为与纯种物种相似，可改善……