Female-biased gene flow between two species of Darwin’s finches Academic Article uri icon

abstract

  • 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 Galápagos 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.

altmetric score

  • 113.37

author list (cited authors)

  • Lamichhaney, S., Han, F., Webster, M. T., Grant, B. R., Grant, P. R., & Andersson, L.

citation count

  • 4

publication date

  • May 2020