Genomic evidence for convergent evolution of a key trait underlying divergence in island birds

Elizabeth A. Cooper, J. Albert Uy

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)3760-3774
Number of pages15
JournalMolecular Ecology
Volume26
Issue number14
DOIs
StatePublished - Jul 1 2017

Fingerprint

convergent evolution
Islands
plumage
Birds
genomics
divergence
bird
birds
Population
reproductive isolation
Color
Reproductive Isolation
gene
color
Single Nucleotide Polymorphism
Melanesia
common ancestry
background level
Genes
taxonomy

Keywords

  • convergent evolution
  • ddRAD sequencing
  • divergence
  • Monarcha
  • speciation with gene flow

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics

Cite this

Genomic evidence for convergent evolution of a key trait underlying divergence in island birds. / Cooper, Elizabeth A.; Uy, J. Albert.

In: Molecular Ecology, Vol. 26, No. 14, 01.07.2017, p. 3760-3774.

Research output: Contribution to journalArticle

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