Data from: The hologenomic basis of speciation: gut bacteria cause hybrid lethality in the genus Nasonia

Although the gut microbiome influences numerous aspects of organismal fitness, its role in animal evolution and the origin of new species is largely unknown. Here we present evidence that beneficial bacterial communities in the guts of closely related species of the genus Nasonia form species-specific phylosymbiotic assemblages that cause lethality in interspecific hybrids. Bacterial constituents and abundance are irregular in hybrids relative to parental controls, and antibiotic curing of the gut bacteria significantly rescues hybrid survival. Moreover, feeding bacteria to germ-free hybrids reinstates lethality and recapitulates the expression of innate immune genes observed in conventionally reared hybrids. We conclude that in this animal complex, the gut microbiome and host genome represent a coadapted “hologenome” that breaks down during hybridization, promoting hybrid lethality and assisting speciation.

尽管肠道微生物组（gut microbiome）可影响机体适合度的诸多方面，但其在动物演化与新物种起源中的作用仍尚未明确。本研究提供证据表明：丽蝇蛹集金小蜂属（Nasonia）近缘物种肠道内的有益细菌群落，会形成物种特异性的系统共生（phylosymbiotic）菌群结构，该结构会在种间杂种中引发致死效应。与亲本对照组相比，种间杂种的细菌组成与丰度均存在异常；通过抗生素清除肠道细菌，可显著挽救杂种的存活能力。此外，将细菌饲喂给无菌杂种，可恢复其致死表型，并重现常规饲养杂种中观察到的先天免疫基因表达模式。综上，在该动物类群复合体中，肠道微生物组与宿主基因组共同构成了一套协同适应的‘全基因组（hologenome）’，该结构在杂交过程中发生崩解，进而促进杂种致死并推动物种形成。