Purging and accumulation of genetic load in conservation

Our ability to assess the threat posed by the genetic load to small and declining populations has been greatly improved by advances in genome sequencing and computational approaches. Yet, considerable confusion remains around the definitions of the genetic load and its dynamics, and how they impact individual fitness and population viability. We illustrate how both selective purging and drift affect the distribution of deleterious mutations during population size decline and recovery. We show how this impacts the composition of the genetic load, and how this affects the extinction risk and recovery potential of populations. We propose a framework to examine load dynamics and advocate for the introduction of load estimates in the management of endangered populations.

Automated summary

Advances in genome sequencing and computational approaches have greatly improved our ability to assess the threat posed by the genetic load to small and declining populations. However, confusion remains regarding the definitions of genetic load and its dynamics, and their impact on individual fitness and population viability. This study demonstrates the effects of both selective purging and drift on the distribution of deleterious mutations during population decline and recovery, and how this impacts the genetic load composition, extinction risk, and recovery potential of populations. The authors propose a framework for studying load dynamics and advocate for the use of load estimates in the management of endangered populations.