Nat Commun. 2014 Dec 16;5:5495. doi: 10.1038/ncomms6495.

Transposable element islands facilitate adaptation to novel environments in an invasive species.

Schrader L¹, Kim JW², Ence D³, Zimin A⁴, Klein A¹, Wyschetzki K¹, Weichselgartner T¹, Kemena C⁵, Stökl J¹, Schultner E⁶, Wurm Y⁷, Smith CD⁸, Yandell M⁹, Heinze J¹, Gadau J¹⁰, Oettler J¹.

Author information

1: Institut für Zoologie, Universität Regensburg, 93053 Regensburg, Germany.
2: Department of Biomolecular Engineering, University of California at Santa Cruz, Santa Cruz, California 95064, USA.
3: Eccles Institute of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA.
4: Institute for Physical Sciences and Technology, University of Maryland, College Park, Maryland 20742, USA.
5: Institute for Evolution and Biodiversity, Westfälische Wilhelms-Universität, 48149 Münster, Germany.
6: Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland.
7: School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
8: Department of Biology, San Francisco State University, San Francisco, California 94132, USA.
9: 1] Eccles Institute of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA [2] Utah Center for Genetic Discovery, University of Utah, Salt Lake City 84112, USA.
10: School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA.

Abstract

Adaptation requires genetic variation, but founder populations are generally genetically depleted. Here we sequence two populations of an inbred ant that diverge in phenotype to determine how variability is generated. Cardiocondyla obscurior has the smallest of the sequenced ant genomes and its structure suggests a fundamental role of transposable elements (TEs) in adaptive evolution. Accumulations of TEs (TE islands) comprising 7.18% of the genome evolve faster than other regions with regard to single-nucleotide variants, gene/exon duplications and deletions and gene homology. A non-random distribution of gene families, larvae/adult specific gene expression and signs of differential methylation in TE islands indicate intragenomic differences in regulation, evolutionary rates and coalescent effective population size. Our study reveals a tripartite interplay between TEs, life history and adaptation in an invasive species.