Recurrent introgression and geographical stratification shape Saccharomyces cerevisiae in the Neotropics

Area of Science:

• Evolutionary Biology
• Genomics
• Microbiology

Background:

• Introgressive hybridization is a key driver of evolutionary history, introducing genetic diversity across organisms from yeasts to humans.
• Saccharomyces cerevisiae strains globally show introgressions from the closely related species S. paradoxus, despite sequence divergence exceeding 10%.

Purpose of the Study:

• To investigate the unclear origins of introgressions in Neotropical Saccharomyces cerevisiae isolates.
• To characterize the genetic diversity and population structure of S. cerevisiae from spontaneous agave fermentations in Mexico.

Main Methods:

• Sequencing of 216 Saccharomyces cerevisiae isolates from Mexican agave fermentations.
• Genomic analysis to reveal genetic diversity, population structure, and introgression patterns.
• Phylogenetic analysis incorporating data from other Neotropical regions.

Main Results:

• Significant genetic diversity and geographically linked population structure were identified in Mexican S. cerevisiae strains.
• A broader Neotropical phylogenetic cluster, enriched in introgressions, was established including strains from Mexico, French Guiana, Ecuador, and Brazil.
• Evidence for multiple hybridization events and conserved introgression patterns suggests flexible species barriers in the Neotropics.

Conclusions:

• Geographical stratification and multiple introgressions concurrently shape the genomes of diverse S. cerevisiae lineages.
• Neotropical yeasts serve as a valuable model for studying the mechanisms and adaptive significance of introgressive hybridization in eukaryotes.