TY - JOUR
T1 - Genomic evidence for convergent evolution of a key trait underlying divergence in island birds
AU - Cooper, Elizabeth A.
AU - Uy, J. Albert C.
N1 - Funding Information:
Permission to work in the Solomon Islands was granted by the Ministry of Environment, Climate Change, Disaster Management & Meteorology, Solomon Islands. For assistance in the Solomons, we thank the Murray family, H. Pirigua and the staff and students of Pawa Secondary School, Ugi Island. We especially thank Lonsdale Taka, James Suafuria and George Wabeasi for excellent field assistance. We thank William Hulme and the staff of the Hussman Institute of Human Genetics at the University of Miami for performing the sequencing for this study. We also thank the University of Miami Center for Computational Science and the Clemson Computing and Information Technology centre for providing many of the computing resources used in our analyses. For discussion and suggestions, we thank D.C. Presgraves, A. Lawton-Rauh, J. McCormack, D. Irrwin and B. Faircloth, as well as members of the Uy and William Searcy laboratories and three anonymous reviewers. This work was funded by a National Science Foundation CAREER award (1137624), a National Geographic Society CRE award (9023-11), the College of Arts & Sciences at the University of Miami and the Aresty Chair in Tropical Ecology.
Publisher Copyright:
© 2017 John Wiley & Sons Ltd
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/7
Y1 - 2017/7
N2 - Reproductive isolation can be initiated by changes in one or a few key traits that prevent random mating among individuals in a population. During the early stages of speciation, when isolation is often incomplete, there will be a heterogeneous pattern of differentiation across regions of the genome between diverging populations, with loci controlling these key traits appearing the most distinct as a result of strong diversifying selection. In this study, we used Illumina-sequenced ddRAD tags to identify genomewide patterns of differentiation in three recently diverged island populations of the Monarcha castaneiventris flycatcher of the Solomon Islands. Populations of this species have diverged in plumage colour, and these differences in plumage colour, in turn, are used in conspecific recognition and likely important in reproductive isolation. Previous candidate gene sequencing identified point mutations in MC1R and ASIP, both known pigmentation genes, to be associated with the difference in plumage colour between islands. Here, we show that background levels of genomic differentiation based on over 70,000 SNPs are extremely low between populations of distinct plumage colour, with no loci reaching the level of differentiation found in either candidate gene. Further, we found that a phylogenetic analysis based on these SNPs produced a taxonomy wherein the two melanic populations appear to have evolved convergently, rather than from a single common ancestor, in contrast to their original classification as a single subspecies. Finally, we found evidence that the pattern of low genomic differentiation is the result of both incomplete lineage sorting and gene flow between populations.
AB - Reproductive isolation can be initiated by changes in one or a few key traits that prevent random mating among individuals in a population. During the early stages of speciation, when isolation is often incomplete, there will be a heterogeneous pattern of differentiation across regions of the genome between diverging populations, with loci controlling these key traits appearing the most distinct as a result of strong diversifying selection. In this study, we used Illumina-sequenced ddRAD tags to identify genomewide patterns of differentiation in three recently diverged island populations of the Monarcha castaneiventris flycatcher of the Solomon Islands. Populations of this species have diverged in plumage colour, and these differences in plumage colour, in turn, are used in conspecific recognition and likely important in reproductive isolation. Previous candidate gene sequencing identified point mutations in MC1R and ASIP, both known pigmentation genes, to be associated with the difference in plumage colour between islands. Here, we show that background levels of genomic differentiation based on over 70,000 SNPs are extremely low between populations of distinct plumage colour, with no loci reaching the level of differentiation found in either candidate gene. Further, we found that a phylogenetic analysis based on these SNPs produced a taxonomy wherein the two melanic populations appear to have evolved convergently, rather than from a single common ancestor, in contrast to their original classification as a single subspecies. Finally, we found evidence that the pattern of low genomic differentiation is the result of both incomplete lineage sorting and gene flow between populations.
KW - Monarcha
KW - convergent evolution
KW - ddRAD sequencing
KW - divergence
KW - speciation with gene flow
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U2 - 10.1111/mec.14116
DO - 10.1111/mec.14116
M3 - Article
C2 - 28370617
AN - SCOPUS:85018578629
VL - 26
SP - 3760
EP - 3774
JO - Molecular Ecology
JF - Molecular Ecology
SN - 0962-1083
IS - 14
ER -