Genetic analysis of flower color differences between a hummingbird-pollinated and a self-pollinated monkeyflower (Mimulus) species

Flower color plays an important role in pollinator discrimination and speciation. Understanding the genetic contributions to flower color differences between two closely related species, Mimulus cardinalis and Mimulus parishii, can improve understanding of how they developed different pollination syndromes and diverged from a recent common ancestor. M. cardinalis is hummingbird-pollinated and has large, bright red flowers while M. parishii is self-pollinated and has small, pale pink flowers. An F2 hybrid population between these two species was created to establish a platform for analysis of the genetic architecture controlling the differences in anthocyanin pigmentation. Statistical analysis of anthocyanin concentration distribution in the hybrid population indicated that two major loci control anthocyanin variation between M. cardinalis and M. parishii. Genetic mapping, in conjunction with the development of near-isogenic lines through serial backcrossing, located one of the major loci to a 750-kb region on chromosome four. I have also generated a near-isogenic line to isolate the other major locus. Together, my thesis work represents substantial progress towards identifying the specific genes underlying the dramatic flower color variation between a hummingbird-pollinated and a self-pollinated Mimulus species