Abstract

By analysing pooled whole-genome sequences from two species of Darwin's finches, both before and after interbreeding and back-crossing, the authors show that gene exchange between the two species is asymmetric and female biased.The mosaic nature of hybrid genomes is well recognized, but little is known of how they are shaped initially by patterns of breeding, selection, recombination and differential incompatibilities. On the small Galapagos island of Daphne Major, two species of Darwin's finches, Geospiza fortis and G. scandens, hybridize rarely and back-cross bidirectionally with little or no loss of fitness under conditions of plentiful food. We used whole-genome sequences to compare genomes from periods before and after successful interbreeding followed by back-crossing. We inferred extensive introgression from G. fortis to G. scandens on autosomes and mitochondria but not on the Z chromosome. The unique combination of long-term field observations and genomic data shows that the reduction of gene flow for Z-linked loci primarily reflects female-biased gene flow, arising from a hybrid-male disadvantage in competition for high-quality territories and mates, rather than from genetic incompatibilities at Z-linked loci.

Published in

Nature ecology & evolution
2020, Volume: 4, pages: 979-986
Publisher: NATURE PUBLISHING GROUP

SLU Authors

• Andersson, Leif

  • Department of Animal Biosciences, Swedish University of Agricultural Sciences
    
  • Texas A&M University
  • Uppsala University

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1038/s41559-020-1183-9

Permanent link to this page (URI)

https://res.slu.se/id/publ/105763