University of Oulu

Alan Brelsford, Jessica Purcell, Amaury Avril, Patrick Tran Van, Junxia Zhang, Timothée Brütsch, Liselotte Sundström, Heikki Helanterä, Michel Chapuisat, An Ancient and Eroded Social Supergene Is Widespread across Formica Ants, Current Biology, Volume 30, Issue 2, 2020, Pages 304-311.e4, ISSN 0960-9822,

An ancient and eroded social supergene is widespread across Formica ants

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Author: Brelsford, Alan1,2; Purcell, Jessica3,2; Avril, Amaury2;
Organizations: 1Department of Evolution, Ecology and Organismal Biology, University of California Riverside, Riverside, CA 92521, USA
2Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
3Department of Entomology, University of California Riverside, Riverside, CA 92521, USA
4College of Life Sciences, Hebei University, Baoding, Hebei 071002, China
5Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
6Ecology and Genetics Research Unit, University of Oulu, 90014 Oulu, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link:
Language: English
Published: Elsevier, 2020
Publish Date: 2021-01-02


Supergenes, clusters of tightly linked genes, play a key role in the evolution of complex adaptive variation [1, 2]. Although supergenes have been identified in many species, we lack an understanding of their origin, evolution, and persistence [3]. Here, we uncover 20–40 Ma of evolutionary history of a supergene associated with polymorphic social organization in Formica ants [4]. We show that five Formica species exhibit homologous divergent haplotypes spanning 11 Mbp on chromosome 3. Despite the supergene’s size, only 142 single nucleotide polymorphisms (SNPs) consistently distinguish alternative supergene haplotypes across all five species. These conserved trans-species SNPs are localized in a small number of disjunct clusters distributed across the supergene. This unexpected pattern of divergence indicates that the Formica supergene does not follow standard models of sex chromosome evolution, in which distinct evolutionary strata reflect an expanding region of suppressed recombination [5]. We propose an alternative “eroded strata model” in which clusters of conserved trans-species SNPs represent functionally important areas maintained by selection in the face of rare recombination between ancestral haplotypes. The comparison of whole-genome sequences across 10 additional Formica species reveals that the most conserved region of the supergene contains a transcription factor essential for motor neuron development in Drosophila [6]. The discovery that a very small portion of this large and ancient supergene harbors conserved trans-species SNPs linked to colony social organization suggests that the ancestral haplotypes have been eroded by recombination, with selection preserving differentiation at one or a few genes generating alternative social organization.

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Series: Current biology
ISSN: 0960-9822
ISSN-E: 1879-0445
ISSN-L: 0960-9822
Volume: 30
Issue: 2
Pages: 304 - 311
DOI: 10.1016/j.cub.2019.11.032
Type of Publication: A1 Journal article – refereed
Field of Science: 1181 Ecology, evolutionary biology
1184 Genetics, developmental biology, physiology
Funding: Funding was provided by Swiss National Science Foundation grants 31003A-146641 and 31003A-173189 (to M.C.) and the University of Lausanne and University of California, Riverside.
Copyright information: © 2020 The Authors. Published by Elsevier Inc. This manuscript version is made available under the CC-BY-NC-ND 4.0 license