Genetic basis of reproductive isolation in Solanum Sect. Lycopersicon

Indiana University, Bloomington IN

Investigators

Abstract

Species are isolated from each other by barriers to reproduction, so that their hybrids are generally inviable and/or sterile. The research proposal involves three projects that examine the genetic basis of species reproductive isolating barriers in the plant group that includes the domesticated tomato, Solanum lycopersicum. First, the chromosomal location of genes that contribute to species barriers will be identified using "trait mapping" in hybrid populations between two species. Second, the degree to which different species share the same reproductive isolating genes will be examined using classical genetic crosses between hybrid genotypes. Third, the specific genes that lie within identified chromosomal regions will be uncovered, using recombinational "fine-mapping" with molecular genetic markers. Identifying the genes that cause hybrid sterility can provide insight into fundamental biological processes, including how new species are formed, and which genes contribute to reproductive functions. In addition, this research has practical applications. Wild relatives of agronomically-important species, such as tomato, are useful sources of natural genetic variation (e.g. for disease resistance, or tolerance to drought stress). Understanding the genetic mechanisms of reproductive isolation between these species can aid in developing breeding strategies to overcome these sterility barriers during crop improvement.