Speciation driven by hybridization and chromosomal plasticity in a wild yeast

This week we will discuss a paper on how chromosomal rearrangements and hybridization between two yeast lineages drive hybrid speciation after secondary contact. The paper is authored by Leducq and co-authors and is available from BioRxiv, a bit fresher than most papers we read and hopefully with plenty of scope for discussion.

Speciation driven by hybridization and chromosomal plasticity in a wild yeast 



Hybridization is recognized as a powerful mechanism of speciation and a driving force in generating biodiversity. However, only few multicellular species, limited to a handful of plants and animals, have been shown to fulfill all the criteria of homoploid hybrid speciation. This lack of evidence could lead to the misconception that speciation by hybridization has a limited role in eukaryotes, particularly in single-celled organisms. Laboratory experiments have revealed that fungi such as budding yeasts can rapidly develop reproductive isolation and novel phenotypes through hybridization, showing that in principle homoploid speciation could occur in nature. Here we report a case of homoploid hybrid speciation in natural populations of the budding yeast Saccharomyces paradoxus inhabiting the North American forests. We show that the rapid evolution of chromosome architecture and an ecological context that led to secondary contact between nascent species drove the formation of an incipient hybrid species with a potentially unique ecological niche. 

Published Sep. 29, 2015 2:57 PM