A genome-wide investigation of adaptive signatures in protein-coding genes related to tool behaviour in New Caledonian and Hawaiian crows

Funding: A David Phillips Fellowship to C.R. from the UK’s Biotechnology and Biological Sciences Research Council (BBSRC; grant BB/G023913/2). Further funding for personnel and data generation of the remaining species was provided by the European Research Council (ERCStG-336536 FuncSpecGen to J.B.W.W.), the Swedish Research Council Vetenskapsrådet (621-2013-4510 to J.B.W.W.), the Knut and Alice Wallenberg Foundation (to J.B.W.W.), the Lawski foundation (to V.E.K. and J.B.W.W.) and the German Research Foundation (KU 3402/1-1 to V.E.K.). A Marsden Fund Grant to G.R.H., R.D.G. and N.J.G. from the Royal Society of New Zealand (UOA1208), a Japanese Society for Promotion of Science Postdoctoral Fellowship (H.A.), together with funding from University of Auckland (G.R.H. and R.D.G.), the Department of Linguistic and Cultural Evolution at the Max Planck Institute for the Science of Human History, and University of Otago (N.J.G.). N.D. acknowledges funding from the Swiss National Science Foundation (P2SKP3_165031 and P300PA_177845) and the Carl Tryggers Foundation.Very few animals habitually manufacture and use tools. It has been suggested that advanced tool behaviour co-evolves with a suite of behavioural, morphological and life-history traits. In fact, there are indications for such an adaptive complex in tool-using crows (genus Corvus species). Here, we sequenced the genomes of two habitually tool-using and ten non-tool-using crow species to search for genomic signatures associated with a tool-using lifestyle. Using comparative genomic and population genetic approaches, we screened for signals of selection in protein-coding genes in the tool-using New Caledonian and Hawaiian crows. While we detected signals of recent selection in New Caledonian crows near genes associated with bill morphology, our data indicate that genetic changes in these two lineages are surprisingly subtle, with little evidence at present for convergence. We explore the biological explanations for these findings, such as the relative roles of gene regulation and protein-coding changes, as well as the possibility that statistical power to detect selection in recently diverged lineages may have been insufficient. Our study contributes to a growing body of literature aiming to decipher the genetic basis of recently evolved complex behaviour.PostprintPeer reviewe