A high throughput-mating assay between S. cerevisiae natural strains reveals a genetic basis for sexual selection and fitness inheritance

Abstract

Abstract Sexual mating is key to evolutionary processes, allowing combination of beneficial alleles between individuals. Data across species suggest that organisms can exert selection of partners that in part depends on factors such as genetic distance and fitness of partners. Fitness is the ultimate evolutionary trait, and its inheritance as a quantitative trait is multi-genic. Revealing the factors that govern mate selection and fitness inheritance are critical for understanding the effects of sex on evolution. Yet, large data are limited, main conclusions are inconsistent, and bigger and consistent datasets are needed. Here, we developed a massive mating assay that enables the simultaneous quantification of mate choice among ~100 Saccharomyces cerevisiae natural strains. DNA barcode recombination allows sequencing of recombined barcode pairs to reveal mating frequencies among all strains, and fitness measurements of both parental haploids and offspring diploids. We find preferential mating with partners with which higher-fitness offspring emerge. Following inheritance of fitness, we find that offspring fitness in fermentable carbon source correlates mainly with parental fitness, while on non-fermentable carbon, offspring fitness is mainly an increasing function of the genetic distance between their parents. Our results suggest that mate choice and fitness inheritance depend upon environmental condition and strains genetics.