Assisted Gene Flow to Facilitate Local Adaptation to Climate Change

TLDR

Assisted gene flow can mitigate climate‑driven maladaptation but risks outbreeding depression and may disrupt local adaptation to nonclimatic factors. Simulations show that selection can remove extrinsic outbreeding depression and that evolution can resolve mild intrinsic epistatic effects within a few generations, indicating AGF is a powerful tool for large, broadly distributed species with historical local climatic adaptation.

Abstract

Assisted gene flow (AGF) between populations has the potential to mitigate maladaptation due to climate change. However, AGF may cause outbreeding depression (especially if source and recipient populations have been long isolated) and may disrupt local adaptation to nonclimatic factors. Selection should eliminate extrinsic outbreeding depression due to adaptive differences in large populations, and simulations suggest that, within a few generations, evolution should resolve mild intrinsic outbreeding depression due to epistasis. To weigh the risks of AGF against those of maladaptation due to climate change, we need to know the species' extent of local adaptation to climate and other environmental factors, as well as its pattern of gene flow. AGF should be a powerful tool for managing foundation and resource-producing species with large populations and broad ranges that show signs of historical adaptation to local climatic conditions.