We find continuous phenotypic and genomic adaptation in response to rapid environmental change in Drosophila - preprint doi: https://doi.org/10.1101/2021.04.27.441526
Work co-led by @SethRudman, @sharGblum, and @RajpurohitLab and in collaboration with @PetrovADmitri. 1/5

Using field mesocosms we tracked phenotypic adaptation as parallel change across replicate populations over monthly intervals. All six phenotypes evolved in parallel, but rates and even the direction of adaptation varied over time. Rates of adaptation were fast…extremely fast.

Also tracked adaptation as parallel changes in allele frequencies over time. As with phenotypes, we found widespread parallel shifts across intervals. Even better, the direction of AF shifts at outlier sites changed over time, demonstrating strong and fluctuating selection.

The genomic architecture of adaptation varied over each time interval, and adaptation operated at multiple timescales. Inversions didn’t drive patterns, but linkage was important. When assessing change through linked sites (‘clusters’), selection was also strong and fluctuating.

A simple field experiment: large populations evolving over ~10 generations in response to natural, seasonal changes in the environment. With temporal resolution and replication, genomic and phenotypic patterns are clear. Could adaptive tracking be pervasive but unseen?