Many interspecific chromosomal introgressions are highly prevalent in HolarcticSaccharomyces uvarumstrains found in human-related fermentations

In the last two decades, the massive genome sequencing of strains belonging to the Saccharomyces genus revealed the complex reticulated evolution of this group. Among the various evolutionary mechanisms described, the introgression of large chromosomal regions resulting from interspecific hybridization has recently shed light on the Saccharomyces uvarum species. In this work we provide the de novo assembled genomes of four S. uvarum strains presenting more than 712 kb of introgressed loci inherited from both S. eubayanus and S. kudriavzevii species. In order to study the prevalence of such introgressions in a large population, we designed multiplexed PCR- markers able to survey the inheritance of 8 chromosomal regions. Our data confirm that introgressions are widely disseminated in Holarctic S. uvarum population and are more frequently found in strains isolated from human-related fermentations. According to the origin of the strains (nature, cider or wine related process) some loci are overrepresented suggesting their positive selection by human activity. Except one locus located on chromosome 7, the introgressions present a low level of heterozygozity similar to that observed for nine neutral markers (microsatellites). Finally, most of these loci tested showed an expected Mendelian segregation after meiosis and can recombined with their chromosomal counterpart in S. uvarum.