Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland.
Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France.
Proc Natl Acad Sci U S A. 2022 Aug 23;119(34):e2201040119. doi: 10.1073/pnas.2201040119. Epub 2022 Aug 15.
Supergenes are clusters of tightly linked genes that jointly produce complex phenotypes. Although widespread in nature, how such genomic elements are formed and how they spread are in most cases unclear. In the fire ant and closely related species, a "social supergene controls whether a colony maintains one or multiple queens. Here, we show that the three inversions constituting the () supergene emerged sequentially during the separation of the ancestral lineages of and . The two first inversions arose in the ancestral population of both species, while the third one arose in the lineage. Once completely assembled in the lineage, the supergene first introgressed into , and from there into the other species of the socially polymorphic group of South American fire ant species. Surprisingly, the introgression of this large and important genomic element occurred despite recent hybridization being uncommon between several of the species. These results highlight how supergenes can readily move across species boundaries, possibly because of fitness benefits they provide and/or expression of selfish properties favoring their transmission.
超级基因是紧密连锁的基因簇，共同产生复杂的表型。尽管在自然界中广泛存在，但这些基因组元件是如何形成的以及它们是如何传播的，在大多数情况下尚不清楚。在红火蚁及其密切相关的物种中，“社会超级基因”控制着一个蚁群是维持一个还是多个蚁后。在这里，我们表明，构成（）超级基因的三个倒位在红火蚁和红火蚁的祖先谱系分离过程中依次出现。前两个倒位出现在两个物种的祖先种群中，而第三个倒位出现在红火蚁谱系中。一旦完全组装在红火蚁谱系中，超级基因首先渗入红火蚁，然后从红火蚁渗入其他具有社会性多态性的南美红火蚁物种。令人惊讶的是，尽管几个物种之间最近的杂交并不常见，但这个大型和重要的基因组元件的渗入还是发生了。这些结果强调了超级基因如何能够轻易地跨越物种界限移动，可能是因为它们提供了适应性优势，或者表达了有利于它们传播的自私特性。
