Genomic variation, population history and within-archipelago adaptation between island bird populations

• Published in: Royal Society Open Science
• Main Authors: Martin, Claudia A., Armstrong, Claire, Illera, Juan Carlos, Emerson, Brent C., Richardson, David S., Spurgin, Lewis G.
• Other Authors: Natural Environment Research Council (UK), Norwich Research Park, British Ecological Society, Gobierno de Canarias, Ministerio de Medio Ambiente (España), Governo Regional da Madeira
• Format: Article in Journal/Newspaper
• Language: English
• Published: Royal Society (Great Britain) 2021
• Subjects: Adaptation; Population genetics; Birds; Colonization history; Genome scan; Spatial scales; North Atlantic
• Online Access: http://hdl.handle.net/10261/240029; https://doi.org/10.1098/rsos.201146; https://doi.org/10.13039/501100000409; https://doi.org/10.13039/501100000270

Oceanic island archipelagos provide excellent models to understand evolutionary processes. Colonization events and gene flow can interact with selection to shape genetic variation at different spatial scales. Landscape-scale variation in biotic and abiotic factors may drive fine-scale selection within islands, while long-term evolutionary processes may drive divergence between distantly related populations. Here, we examine patterns of population history and selection between recently diverged populations of the Berthelot's pipit (Anthus berthelotii), a passerine endemic to three North Atlantic archipelagos. First, we use demographic trees and f3 statistics to show that genome-wide divergence across the species range is largely shaped by colonization and bottlenecks, with evidence of very weak gene flow between populations. Then, using a genome scan approach, we identify signatures of divergent selection within archipelagos at single nucleotide polymorphisms (SNPs) in genes potentially associated with craniofacial development and DNA repair. We did not detect within-archipelago selection at the same SNPs as were detected previously at broader spatial scales between archipelagos, but did identify signatures of selection at loci associated with similar biological functions. These findings suggest that similar ecological factors may repeatedly drive selection between recently separated populations, as well as at broad spatial scales across varied landscapes. This work was supported by Natural Environment Research Council (NERC) studentships to C.A.M. and C.A. (NE/L002582/1), a Norwich Research Park Science Links grant to D.S.R., M.C. and L.G.S., and a BBSRC fellowship (BB/N011759/1) and British Ecological Society Large Research Grant to L.G.S.We thank two anonymous reviewers whose insight and helpful suggestions have improved this manuscript. We thank Matthew Clark and Lawrence Percival-Alwyn for assistance generating the Berthelot's pipit genome, and Helen Hipperson, Clemens Küpper and Terry Burke (NERC ...