All flowering plants possess two or more copies of every chromosome. Polyploidy is thought to be a main driver of plant speciation, biological adaptation and range expansion. How chromosome doubling contributes to biodiversity, and which genomic mechanisms or functional traits underlie the success of polyploids, remain unanswered questions.

This project will focus on wild species of strawberry (genus Fragaria). Nearly half of the 20 species of wild strawberry are polyploid and the genus has centers of diversity in China and North America. Strawberries possess numerous features (small genome, clonal propagation, availability of synthetic neopolyploids, sensitivity to climate change due to early-spring flowering and northern latitude or high elevation distribution) that make them an outstanding model system to better understand how genome doubling contributes to biodiversity. Research will focus on seven 'trios' of polyploid species and their diploid progenitors, native to North America, Europe and East Asia. Extensive field work will be conducted in China, focused on East Asian species that are poorly known ecologically and taxonomically.

This research will establish whether similarities in functional diversity and ecological amplitude of polyploid species are the result of common rules of genetic diversity, chromosome structure or gene expression in a polyploid genome, or whether multiple genetic and genomic pathways lead to successful responses to environmental change. Deep phylogenetic and population genomic sampling will determine whether multiple independent origins contribute to functional and genetic diversity of natural polyploids. The characterization of trait and gene expression in natural and synthetic polyploids, and their diploid progenitors, under climatically diverse experimental gardens (eastern USA, western USA, China) will identify how functional and genetic diversity are distributed in a polyploid/diploid lineage. The integration of these results will inform efforts to predict the effect of whole genome duplication on ecological and evolutionary responses to environmental change in numerous other plant lineages.

This project will accelerate our understanding of how genome doubling confers success, and how it contributes to biodiversity across geographic and evolutionary scales. Moreover, this deeply integrated comparative study of the wild relatives of the cultivated strawberry — a polyploid species of world-wide economic importance — will provide foundational knowledge and contribute unparalleled resources that may be harnessed in efforts to ensure sustainability of strawberry and related crops (e.g., cherry, peach, pear, apple) in the face of abiotic stress. The work will promote training by broad participation and international collaboration, and novel hands-on science curriculum for middle school and undergraduate students.