Analysis of population genetic structure and gene flow in an annual plant before and after a rapid evolutionary response to drought

Climate change can have widespread and devastating impacts, but little is known about the effects of this change on the genetics of natural populations. In a new study published in AoB PLANTS, Welt et al. aimed to examine the effect of a climate change event on gene flow over space and time in two populations of Brassica rapa that evolved more synchronous flowering times over five years of drought in southern California. They found limited genetic differences between pre-drought ancestors and post-drought descendants, indicating that the two populations did not become more genetically similar, despite a greater overlap in reproductive timing after the drought. The findings of this study contribute to an understanding of the genetic impacts of climate change, which is critical in optimizing conservation efforts.