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Genomics of hybridization, speciation and phenotypic evolution in wheatears

Insights into the molecular underpinnings and natural history of phenotypic and species evolution

Nature is home to a splendid diversity of phenotypes and species, yet we only begin to unravel the complex molecular and evolutionary mechanisms underpinning the many ways in which species and individuals differ. Owing to recent technological revolutions, we now have unprecedented access to genome-wide molecular diversity and can start tackling some of the most pertinent questions on the evolution of this biodiversity: What are the molecular bases of phenotypic adaptation and species‘ boundaries? Which roles do already existing genetic variants, novel genetic variants, and the genetic exchange of genetic variants upon hybridization play in the evolution of phenotypes and species?

Domain Research
Unit Ecological research
Topic Evolution
Habitat rocky terrain, wasteland
Project start 2020
Project status ongoing
Project management Reto Burri
Project region Africa, Asia, Europe


Project objectives

We aim to obtain insights into the molecular bases and evolutionary history of convergent phenotypic evolution and speciation in a unique system of colour-polymorphic songbirds – wheatears of the Oenanthe hispanica complex. Making use of the natural laboratory provided by pervasive hybridization in this complex replicated in several geographic regions, we aim to:

  • Identify genomic regions underpinning plumage coloration and reconstruct color evolutionary history.
  • Determine genomic regions resisting gene flow in all hybrid zones that likely act as species barriers.
  • Understand the role of mobile genetic elements and chromosome rearrangements in phenotypic evolution and speciation.


To infer the genetic variation underpinning convergent color evolution and species barriers in wheatears, we interrogate cutting-edge whole-genome sequence data of (1) the hispanica complex from populations all over the range and (2) nearly all species of wheatears. We identify genomic regions underpinning plumage coloration in the hispanica complex and species barriers by, respectively, leveraging phenotypic polymorphisms or admixture in hybrid zones. We then use the information contained in these genomic regions to reconstruct the evolutionary history of the trait they underpin.


Phylogenetic analyses of whole genomes of most wheatear species and close relatives suggest that convergent phenotypic evolution in these species involved incomplete sorting of ancestral variation, introgression, and novel mutations. This conclusion is supported by our work in the O. hispanica complex. By tracing the underlying genetic variation we showed that the throat color polymorphism found in three species is ancestral to the complex; black back coloration newly evolved in pied wheatear from where it introgressed into Cyprus wheatear; and convergent throat and back color evolution at genus level is not explained by the same variation and thus must be based on novel mutations.

Project partner(s)

Financial support



Species concerned

Bird species
Black-eared Wheatear
The odd Black-eared Wheatear may conceal itself among numerous wheatears that stop over on open farmland in spring. It is of a very variable colour, for apart from two subspecies, there are dark-throated and pale-throated birds in both sexes throughout the whole area of distribution.
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Ecological research link

Ecological research

We investigate the diverse interactions of birds with their environment, from individual settlement behaviour to species communities.

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