The European corn borer moth (ECB) has two pheromone strains, between which gene exchange is limited by differences in pheromone communication and (at some localities) by differences in life cycle. Richard Harrison's project focuses on characterizing the genetic structure of ECB populations and divergence between strains and will examine DNA sequence variation for multiple regions across the ECB genome. In the context of a genetic linkage map, differentiated regions of the genome (regions in which gene flow between strains is low or absent) will be identified and characterized. The importance of major genes that determine pheromone communication and life cycle will be evaluated as potential barriers to gene exchange.
ECB provides an exceptional model system for examining the genetic causes and consequences of reproductive isolation and how patterns of gene exchange vary with genome region. Characterizing gene flow in natural populations is essential for understanding to what extent new variants will spread. The fundamental observation that the amount of gene flow depends on genomic region has potentially profound implications, not only for control of ECB populations (which are major economic pests), but also in other contexts, e.g., with respect to the issue of hybridization between transgenic plants and their wild relatives and for conservation of threatened or endangered populations/species.
