Data from: A socially polymorphic Formica ant species exhibits a novel distribution of social supergene genotypes

Most supergenes discovered so far are young, occurring in one species or a few closely related species. An ancient supergene in the ant genus Formica presents an unusual opportunity to compare supergene-associated phenotypes and the factors that influence the persistence of polymorphism in different species. We investigate the genetic architecture of social organization in Formica francoeuri, an ant species native to low and mid-elevation semiarid regions of southern California, and describe an efficient technique for estimating mode of social organization using population genomic data. Using this technique, we show that F. francoeuri exhibits polymorphism in colony social organization and that the phenotypic polymorphism is strongly associated with genotypes within the Formica social supergene region. The distribution of supergene haplotypes in F. francoeuri differs from that of related species Formica selysi, Formica cinerea, and Formica lemani in that colonies with multiple queens contain almost exclusively workers that are heterozygous for alternative supergene haplotypes. Moreover, heterozygous workers exhibit allele-specific expression of the polygyne-associated haplotype at the candidate gene Knockout, which is thought to influence social organization. We also report geographic population structure and variation in worker size across a large fraction of the species range. Our results suggest that, although the Formica supergene is conserved within the genus, the mechanisms that maintain the supergene and its associated polymorphisms differ among species.

迄今已发现的绝大多数超基因（supergene）均较为年轻，仅分布于单个物种或少数亲缘关系较近的类群中。蚁属（Formica）中的古老超基因，则为比较不同物种中超基因相关表型与影响多态性维持的因素提供了独特契机。本研究针对原产于美国加利福尼亚州南部低海拔至中海拔半干旱区域的弗氏蚁（Formica francoeuri），对其社群组织的遗传架构展开探究，并描述了一种利用群体基因组数据估算蚁群社会组织模式的高效方法。通过该方法，我们证实弗氏蚁的蚁群社会结构存在多态性，且该表型多态性与蚁属社会性超基因区域内的基因型存在显著关联。弗氏蚁体内的超基因单倍型（haplotype）分布与近缘物种西氏蚁（Formica selysi）、灰蚁（Formica cinerea）及莱氏蚁（Formica lemani）存在差异：多后蚁群中几乎仅存在携带两种对立超基因单倍型的杂合工蚁。此外，在被认为可调控蚁群社会组织的候选基因Knockout中，杂合工蚁呈现出与多蚁型相关单倍型的等位基因特异性表达。本研究还报道了该物种大部分分布范围内的地理种群结构与工蚁体型变异。研究结果表明，尽管蚁属超基因在该属内具有保守性，但维持该超基因及其相关多态性的机制在不同物种间存在差异。