Overall, our study found that a chr

Overall, our study found that a chromosomal inversion polymorphism contributes to adaptive divergence and reproductive isolation between annual and perennial ecotypes of M. guttatus. The AN arrangement of the inversion was consistently found in
annual populations and the PE arrangement found in perennial populations distributed over a wide swath of western North America. The inversion polymorphism affected traits associated with this life-history transition across replicated crosses and the
genetic backgrounds of both ecotypes, while contributing to local adaptation, perenniality, and three ecological reproductive isolating barriers under natural field conditions.