QTL analysis of floral morphology polymorphisms between Gilia yorkii and G. capitata

Abstract

Speciation is a complex process typically accompanied by significant genetic and morphological differences between sister populations. In plants, this can result in divergent floral morphologies causing pollinator differences and reproductive isolation between populations. Here, we explore floral trait differences between two recently diverged species, Gilia yorkii and G. capitata. The distributions of floral traits in parental, F1, and F2 populations are compared, and groups of correlated traits are identified. We describe the genetic architecture of floral traits through a quantitative trait locus (QTL) analysis using an F2 population of 187 individuals. While all identified QTLs were of moderate (10-25%) effect, interestingly, many QTL intervals colocalized on Chromosomes 6 and 9, suggesting that sets of traits may share a common genetic basis. Our results provide a framework for future identification of genes involved in the evolution of floral morphology.