Interpreting the genomic landscape of speciation: a road map for finding barriers to gene flow.

Journal Article (Review)

Speciation, the evolution of reproductive isolation among populations, is continuous, complex, and involves multiple, interacting barriers. Until it is complete, the effects of this process vary along the genome and can lead to a heterogeneous genomic landscape with peaks and troughs of differentiation and divergence. When gene flow occurs during speciation, barriers restricting gene flow locally in the genome lead to patterns of heterogeneity. However, genomic heterogeneity can also be produced or modified by variation in factors such as background selection and selective sweeps, recombination and mutation rate variation, and heterogeneous gene density. Extracting the effects of gene flow, divergent selection and reproductive isolation from such modifying factors presents a major challenge to speciation genomics. We argue one of the principal aims of the field is to identify the barrier loci involved in limiting gene flow. We first summarize the expected signatures of selection at barrier loci, at the genomic regions linked to them and across the entire genome. We then discuss the modifying factors that complicate the interpretation of the observed genomic landscape. Finally, we end with a road map for future speciation research: a proposal for how to account for these modifying factors and to progress towards understanding the nature of barrier loci. Despite the difficulties of interpreting empirical data, we argue that the availability of promising technical and analytical methods will shed further light on the important roles that gene flow and divergent selection have in shaping the genomic landscape of speciation.

Full Text

Duke Authors

Cited Authors

  • Ravinet, M; Faria, R; Butlin, RK; Galindo, J; Bierne, N; Rafajlović, M; Noor, MAF; Mehlig, B; Westram, AM

Published Date

  • August 2017

Published In

Volume / Issue

  • 30 / 8

Start / End Page

  • 1450 - 1477

PubMed ID

  • 28786193

Electronic International Standard Serial Number (EISSN)

  • 1420-9101

International Standard Serial Number (ISSN)

  • 1010-061X

Digital Object Identifier (DOI)

  • 10.1111/jeb.13047

Language

  • eng