Signals of selection and ancestry in independently feral G.
gallus populations
Authors: Gering, E#1., Johnsson,
M.#2,3, Theunissen, D.# 2, Martin
Cerezo, M.L.#2, Steep, A.4 Getty,
T.5, Henriksen, R.2, and Wright,
D.*2
Affiliations:
1 Department of Biological Sciences, Halmos College of
Arts and Sciences, Nova Southeastern University, Florida 33314-7796. USA
2 AVIAN Behavioural Genomics and Physiology group, IFM
Biology, Linköping University, Linköping 58183, Sweden
3 Department of Animal Breeding and Genetics, Swedish
University of Agricultural Sciences, 750 07 Uppsala, Sweden
4 Genetics and Genome Sciences Program, Michigan State
University, East Lansing, MI 48824, USA
5 Kellogg Biological Station, Michigan State
University, 3700 East Gull Lake Road, Hickory Corners, MI 49060, USA
# These authors contributed equally
*Corresponding author, email
dominic.wright@liu.se/
domwright@gmail.com
Keywords: Feralisation, Population genomics, Invasion Biology, Adaptive
evolution
Abstract
Recent work indicates that feralisation is not a simple reversal of
domestication, and therefore raises questions about the predictability
of evolution across replicated feral populations. In the present study
we compare genes and traits of two independently established feral
populations of chickens (G. gallus ) that inhabit archipelagos
within the Pacific and Atlantic regions to test for evolutionary
parallelism and/or divergence. We find that feral populations from each
region are genetically similar despite their geographical isolation and
divergent colonization histories.
Next, we used genome scans to identify genomic regions selected during
feralisation (selective sweeps) in two independently feral populations
from Bermuda and Hawaii. Three selective sweep regions (each identified
by multiple detection methods) were shared between feral populations,
and this overlap is inconsistent with a null model in which selection
targets are randomly distributed throughout the genome. In the case of
the Bermudian population, many of the genes present within the selective
sweeps were either not annotated or of unknown function. Of the nine
genes that were identifiable, five were related to behaviour, with the
remaining genes involved in bone metabolism, eye development, and the
immune system.
Our findings suggest that a subset of feralisation loci (i.e. genomic
targets of recent selection in feral populations) are shared across
independently-established populations, raising the possibility that
feralisation involves some degree of parallelism or convergence and the
potential for a shared feralisation ‘syndrome’.