Rapid and repeatable local adaptation in the global invader Ambrosia artemisiifolia

In this thesis, I look for associations among key traits (e.g. flowering time), the environment (e.g. latitude), and genetic variants across the genome in Ambrosia artemisiifolia. I use these data to determine the repeatability of trait evolution in response to similar environments and if the same regions in the genome are involved in determining these patterns. Despite distinct demographic histories of multiple ranges, I provide strong evidence that adaptation occurred rapidly and repeatedly at both the genetic and phenotypic level. This research enhances our understanding of the mechanisms underlying rapid adaptation, key in a world with on-going environmental change.