Associate Professor University of Kentucky Lexington, Kentucky
Speciation is important for creating biodiversity. In sexually reproducing species, speciation is complete when diverging lineages accumulate enough reproductive isolating (RI) barriers that successful interbreeding ceases. However, diverging taxa often come into contact before RI is complete and hybridize. When gene flow occurs, genome regions or alleles that introgress readily may represent alleles that are adaptive in both species, whereas genome regions or alleles showing restricted introgression may represent loci under divergent selection that are important for maintaining divergent lineages. Genome-wide scans for genetic differentiation between hybridizing species are popular and potentially powerful tools for identifying regions of the genome that contribute to species formation. However, interpretation of these scans is complicated by many factors that can impact patterns of differentiation. Also, genome-wide scans are rarely combined with genetic information for traits that may contribute to RI. Here, I combine genome scans between a pair of hybridizing eastern North American pine sawfly species (Neodiprion lecontei and N. pinetum) with data describing non-RI factors that influence differentiation and genetic data for RI traits. Previous experimental work in this system has linked oviposition trait differences to RI and specific gene regions (QTL). While controlling for variation in recombination and mutation rate and gene density across the genome as well as demographic history, I test the hypothesis that loci associated with oviposition differences between N. lecontei and N. pinetum exhibit elevated differentiation in natural populations of this species pair, indicating that they also contribute to RI in the wild.
