TIGP--Experimental Evolution and Genomic Analysis of Mating Preference in Budding Yeast

Prezygotic reproductive isolation that can prevent gene flow 
between closely related species is especially important for 
species that have separated from each other without geographic 
isolation.  Although theoretical models have helped us 
determine the major factors contributing to the evolution of 
prezygotic isolation, very little is known about how a new mating 
preference evolves and its molecular mechanism during the early 
stage of evolution. To study the evolution of prezygotic 
isolation, we have evolved mating discrimination in populations 
of the budding yeast, Saccharomyces cerevisiae.  After 36
cycles of selection, these cells are five times more likely to
mate with each other than to their ancestors, despite detectable 
one-way gene flow between the selected and reference populations.
Several individual cultures evolved mating discrimination by
changing their mating kinetics, indicating that subtle details
of mating behavior can play an important role in the evolution
of reproductive isolation.  By applying a newly developed
genomic mapping method, we found that at least 16 chromosomal
loci are involved in the evolved phenotypes