Poster

         Ecology

Geographic analysis of sex chromosome polymorphism in the Virginia wild strawberry

Presenting Author
Trezalka Budinsky
Description
The evolution of sex chromosomes is a ubiquitous and essential diversifying mechanism in eukaryotes. Yet early stages of sex-chromosome differentiation are poorly understood. The subdioecious octoploid, Fragaria virginiana, provides a rare opportunity to study the beginnings of sex chromosome evolution due to its young, polymorphic ZW sex system. Females are ZW and males/hermaphrodites are ZZ. F. virginiana has a small sex-determining region (SDR) located on the female W chromosome that has undergone three transposition events between the strawberry's four subgenomes, resulting in three SDR haplotypes: alpha (the result of a first transposition and closest to a pre-sex chromosome ancestral state), beta (the result of a second transposition), and gamma (the result of a third transposition and farthest from its ancestral state). We collected leaf tissue from 315 female F. virginiana plants preserved in herbaria and the National Clonal Germplasm Repository. These spanned their North American range. Using diagnostic PCR and gel electrophoresis, we are in the process of inferring each individual's SDR haplotype. Our study aims to advance our understanding of the evolutionary history of sex chromosomes in F. virginiana by examining the geographic distribution of its SDR polymorphism. Specifically, by analyzing the acquired SDR haplotype distribution alongside known environmental variables such as temperature, elevation, and soil type, we seek to elucidate the potential adaptive significance of maintaining all three haplotypes within F. virginiana populations.