TY - JOUR T1 - Highly replicated evolution of parapatric ecotypes JF - bioRxiv DO - 10.1101/2020.02.05.936401 SP - 2020.02.05.936401 AU - Maddie E. James AU - Henry Arenas-Castro AU - Jeffery S. Groh AU - Jan Engelstädter AU - Daniel Ortiz-Barrientos Y1 - 2020/01/01 UR - http://biorxiv.org/content/early/2020/09/27/2020.02.05.936401.abstract N2 - Parallel evolution of ecotypes occurs when selection independently drives the evolution of similar traits across similar environments. The multiple origin of ecotypes is often inferred on the basis of a phylogeny which clusters populations according to geographic location and not by the environment they occupy. However, the use of phylogenies to infer parallel evolution in closely related populations is problematic due to the potential for gene flow and incomplete lineage sorting to uncouple the genetic structure at neutral markers from the colonization history of populations. Here, we demonstrate multiple origins within ecotypes of an Australian wildflower, Senecio lautus. We observed strong genetic structure as well as phylogenetic clustering by geography, and show this is unlikely due to gene flow between parapatric ecotypes, which is surprisingly low. We further confirm this analytically by demonstrating that phylogenetic distortion due to gene flow often requires higher levels of migration than those observed in S. lautus. Our results imply that selection can repeatedly create similar phenotypes despite the perceived homogenizing effects of gene flow.Competing Interest StatementThe authors have declared no competing interest. ER -