Metapopulation dynamics and the influence of the killer system in a natural S. cerevisiae population

Abstract

Populations and their genetic makeup are ever changing. Metapopulations of interconnected small populations, observed over many years, can give us an insight into large-scale shifts in their genetic composition. Here we use a natural metapopulation of Saccharomyces cerevisiae to explore changes in its genetic composition over time. We further examine a possible cause for genetic shifts using the killer-yeast system. We found a large turnover of genotypes over the course of four years with initially few dominant genotypes being replaced by a greater diversity over time. An analysis of dsRNA viruses encoding the killer-yeast genes showed strong changes over time and space. We show partial success with the standard methods to examine the killer-yeast system but also reveal the limits of the current killer assay method when applied on a larger assemblage of natural populations.