Research Team Creates Detailed Map of Genetic Evolution of Brewer's Yeast

A team of researchers from several institutions in France has created a detailed map of the genetic evolution of brewer's yeast (Saccharomyces cerevisiae), the yeast used in making bread, wine, and beer. In their paper published in the journal Nature, the researchers note that S. cerevisiae has been used extensively by humans for a very long time. It is also widely used by research scientists because its genome has been sequenced and can be easily exploited. In this new effort, the researchers sought to learn more about yeast's history by studying its genetic makeup.

The researchers collected yeast samples from around the globe and found that yeast in different parts of the world has changed over time. This is partially due to natural events and partially due to human intervention. Taking a genomic global survey of yeast allowed the researchers to create a map of the evolution of the fungus. The work consisted of performing whole-genome sequencing on 1,011 samples of yeast, which yielded 1,625,809 high-quality reference-based SNPs.

The researchers report that theories of an out-of-China migration of the yeast appear to be true. They also found that yeast has undergone extensive change due to human intervention related to fermentation for making beer, wine, and sake. They noted also that the number of chromosome sets (ploidy) in the yeast cells had an impact on fitness across all of those species tested. They further noted that those with a diploid state appeared to have an advantage over other ploidy types. And they found that yeast has suffered from a loss of heterozygosity, in which there are two distinct alleles of a given gene present. They suggest this has likely led to the wide variation between the samples they observed.

For more information, read the open access paper in Nature.