As best I can tell, yeasts are the only organisms to produce ethanol (and CO2) as the primary end product of metabolism. Some others do, but in lower quantities, and mixed with other, much less appealing compounds.
Given the huge impact alcohol has had on human civilization over the millennia, it's hard to imagine how things would have turned out if this stuff never came along.
I find it interesting, though, that in most of the Chinese cuisine with which I am familiar, yeast-leavened breads seem to be conspicuously absent.
>Large-scale population genomic surveys are essential to explore the phenotypic diversity of natural populations. Here we report the whole-genome sequencing and phenotyping of 1,011 Saccharomyces cerevisiae isolates, which together provide an accurate evolutionary picture of the genomic variants that shape the species-wide phenotypic landscape of this yeast. Genomic analyses support a single ‘out-of-China’ origin for this species, followed by several independent domestication events. Although domesticated isolates exhibit high variation in ploidy, aneuploidy and genome content, genome evolution in wild isolates is mainly driven by the accumulation of single nucleotide polymorphisms. A common feature is the extensive loss of heterozygosity, which represents an essential source of inter-individual variation in this mainly asexual species. Most of the single nucleotide polymorphisms, including experimentally identified functional polymorphisms, are present at very low frequencies. The largest numbers of variants identified by genome-wide association are copy-number changes, which have a greater phenotypic effect than do single nucleotide polymorphisms. This resource will guide future population genomics and genotype–phenotype studies in this classic model system.
Can someone please explain why this is at all plausible? Human beings have been around for a couple hundred thousand years and started from very small populations with long periods between generations. So more genetic variety in Africa makes sense as corroborating the out of Africa theory. But yeast have been around for many millions of years. They have much shorter reproductive cycles. They can spread on the wind long distances. I would expect a geographic origin for yeast to have been long overlaid with all kinds of cross-migrations and lost to time. I just can't make sense of this.
Is there any mention of the time period at which the single yeast common ancestor lived?