Genome divergence and the genetic architecture of barriers to gene flow between Lycaeides idas and L. melissa

Genome divergence during speciation is a dynamic process that is affected by various factors, including the genetic architecture of barriers to gene flow. Herein we quantitatively describe aspects of the genetic architecture of two sets of traits, male genitalic morphology and oviposition preference, that putatively function as barriers to gene flow between the butterfly species Lycaeides idas and L. melissa. Our analyses are based on unmapped DNA sequence data and a recently developed Bayesian regression approach that includes variable selection and explicit parameters for the genetic architecture of traits. A modest number of nucleotide polymorphisms explained a small to large proportion of the variation in each trait, and average genetic variant effects were non-negligible. Several genetic regions were associated with variation in multiple traits or with trait variation within- and among-populations. In some instances genetic regions associated with trait variation also exhibited exc...