"Target Review" in Journal of Evolutionary Biology about hybridization and speciation and a comment

Posted by Erik Svensson

In the latest issue of Journal of Evolutionary Biology there is a so-called "Target Review" by a large group of evolutionary biologists entitled: "Hybridization and speciation".  This review, as well as the comments on it, are published "Open Acccess", meaning that anyone can read and download them, even if you are not in a university library. One of the co-authors of this multi-authored paper is by the way Fabrice Eroukhmanoff, former PhD-student in Lund and past member of the EXEB lab, and currently postdoc in Oslo (Norway).  Below is the Abstract:

Abstract

Hybridization has many and varied impacts on the process of speciation. Hybridization may slow or reverse differentiation by allowing gene flow and recombination. It may accelerate speciation via adaptive introgression or cause near-instantaneous speciation by allopolyploidization. It may have multiple effects at different stages and in different spatial contexts within a single speciation event. We offer a perspective on the context and evolutionary significance of hybridization during speciation, highlighting issues of current interest and debate. In secondary contact zones, it is uncertain if barriers to gene flow will be strengthened or broken down due to recombination and gene flow. Theory and empirical evidence suggest the latter is more likely, except within and around strongly selected genomic regions. Hybridization may contribute to speciation through the formation of new hybrid taxa, whereas introgression of a few loci may promote adaptive divergence and so facilitate speciation. Gene regulatory networks, epigenetic effects and the evolution of selfish genetic material in the genome suggest that the Dobzhansky–Muller model of hybrid incompatibilities requires a broader interpretation. Finally, although the incidence of reinforcement remains uncertain, this and other interactions in areas of sympatry may have knock-on effects on speciation both within and outside regions of hybridization.

The Target Review is, as usual for these types of invited reviews,  followed by a number of comments, some of them critical, by several evolutionary biologists, including myself. My comment can be found here and is entitled: "Beyond hybridization: diversity of interactions with heterospecifics, direct fitness consequences and the effects on mate preferences".  There are also contributions by Nick Barton, Servedio, Hermisson and Dorn, Seehausen, Björklund and Shaw and Mendelson, to mention only a few comments of what seems to be an interesting discussion around a controversial topic, namely the role of hybridization in speciation. Enjoy!