DISSERTATION RESEARCH: QTL Mapping Floral Trait Divergence and Reproductive Isolation between a Jaltomata (Solanaceae) Species Pair

Indiana University, Bloomington IN

Investigators

Abstract

This study aims to identify genes controlling floral trait differences between two species of Jaltomata, a florally diverse genus that is closely related to the economically important genus Solanum (which includes tomato and potato), and to examine whether these genes may also contribute to reproductive barriers between these species. Differences in floral traits are well known to reduce reproduction between species when they attract different pollinators; this study also addresses how such differences may affect success of other reproductive stages, including the survival of hybrids. The flowering plants (Angiosperms) form the foundation of agriculture as well as many of the Earth's ecosystems. This study will advance our understanding of how differences in floral traits may first arise, and how those differences may reduce or prevent reproduction between distinct species. This project will also provide research experiences for undergraduates, including those from groups underrepresented in STEM fields. This work will employ Quantitative Trait Locus (QTL) Mapping to identify genomic regions associated with floral trait differences and multiple reproductive barriers between two species by genotyping an existing hybrid population that has already been phenotyped for these traits. These genomic regions will help determine the genetic basis and evolutionary history shaping floral traits and reproductive barriers in this system. In combination with existing gene expression data from relevant floral and reproductive tissues, the study will also identify candidate genes controlling these processes. These are key steps in understanding the mapping between genotype and phenotype, which is of fundamental importance in both basic and applied biology. Ultimately, this work potentially will provide unique insights into the genetics and evolution of floral diversity, and the mechanistic role of this diversity in promoting speciation.