Hybrid Speciation in Experimental Populations of Yeast

摘要

Most models of speciation require gradual change and geographic or ecological isolation for new species to arise. Homoploid hybrid speciation occurred readily between Saccharomyces cerevisiae and Saccharomyces paradoxus. Hybrids had high self-fertility (about 82%), low fertility when backcrossed to either parental species (about 7.5%), and vigorous growth under different thermal environments that favored one or the other of the parental species. Extensive karyo-typic changes (tetrasomy) were observed in the hybrids, although genie incompatibilities accounted for 50% of the variation in self-fertility.