The Ecology and Evolution of the Baker's Yeast .

The baker's yeast has become a powerful model in ecology and evolutionary biology. A global effort on field survey and population genetics and genomics of in past decades has shown that the yeast distributes ubiquitously in nature with clearly structured populations. The global genetic diversity of is mainly contributed by strains from Far East Asia, and the ancient basal lineages of the species have been found only in China, supporting an 'out-of-China' origin hypothesis. The wild and domesticated populations are clearly separated in phylogeny and exhibit hallmark differences in sexuality, heterozygosity, gene copy number variation (CNV), horizontal gene transfer (HGT) and introgression events, and maltose utilization ability. The domesticated strains from different niches generally form distinct lineages and harbor lineage-specific CNVs, HGTs and introgressions, which contribute to their adaptations to specific fermentation environments. However, whether the domesticated lineages originated from a single, or multiple domestication events is still hotly debated and the mechanism causing the diversification of the wild lineages remains to be illuminated. Further worldwide investigations on both wild and domesticated , especially in Africa and West Asia, will be helpful for a better understanding of the natural and domestication histories and evolution of .