Genomic regions of speciation and adaptation among three species of grouse

Radoslav Kozma,Patrik Rödin-Mörch,Jacob Höglund

doi:10.1038/s41598-018-36880-5

Radoslav Kozma, Patrik Rödin-Mörch + Show 1 more

Open Access

https://doi.org/10.1038/s41598-018-36880-5

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Journal: Scientific Reports	Publication Date: Jan 28, 2019
Citations: 8	License type: open-access

Affiliation: Uppsala University

Abstract

Understanding the molecular basis of adaption is one of the central goals in evolutionary biology and when investigated across sister species it can provide detailed insight into the mechanisms of speciation. Here, we sequence the genomes of 34 individuals from three closely related grouse species in order to uncover the genomic architecture of speciation and the genes involved in adaptation. We identify 6 regions, containing 7 genes that show lineage specific signs of differential selection across the species. These genes are involved in a variety of cell processes ranging from stress response to neural, gut, olfactory and limb development. Genome wide neutrality test statistics reveal a strong signal of population expansion acting across the genomes. Additionally, we uncover a 3.5 Mb region on chromosome 20 that shows considerably lower levels of differentiation across the three grouse lineages, indicating possible action of uniform selection in this region.

Highlights

The identification of genes involved in species’ adaptation to their environment is one of the main aims of evolutionary biology[1]
The aim is to utilise outlier methods to analyse the genomic architecture of species specific differences by exploring the genes involved in adaptation in three grouse; the willow grouse (Lagopus lagopus lagopus), the red grouse (Lagopus lagopus scoticus) and the rock ptarmigan (Lagopus muta)
The red grouse is recognised as a subspecies of the willow grouse[11], it is endemic to the moorlands of Great Britain and Ireland and has been separated from continental populations at least since the time the British Isles separated from mainland Europe (~6000 years ago12,13)

Summary

Introduction

The identification of genes involved in species’ adaptation to their environment is one of the main aims of evolutionary biology[1]. By uncovering the genetic basis of adaptation we improve our understanding of the mechanisms responsible for adaptation and speciation and by which phenotypic diversity arises Until now, this was easier to achieve in domesticated animals where the strong artificial selection and constant, human-monitored environment quickly drove favoured alleles to fixation (e.g. chicken[2] and horses[3]). In order to understand the way natural selection shapes individuals and species, study of wild populations has to be undertaken This allows the examination of the architecture of adaptive traits under natural processes, free from intentional human-driven selection[4,5]. The aim is to utilise outlier methods to analyse the genomic architecture of species specific differences by exploring the genes involved in adaptation in three grouse; the willow grouse (Lagopus lagopus lagopus), the red grouse (Lagopus lagopus scoticus) and the rock ptarmigan (Lagopus muta). The varying levels of arduous habitat and differences in plumage as well as population history provide a compelling system for the study of molecular adaptation and speciation

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