Genetic constraints by small population size

Inbreeding load, and drift load estimated via heterosis in outcrossing and selfing populations of Arabidopsis lyrata. Selfing populations have accumulated substantial drift load (Willi 2013 Evolution)


Genetic constraints by small population size; accumulation of genetic load

In many plants and animals – and not only those of conservation concern – effective population sizes are surprisingly small. Small population size is predicted to lead to the accumulation of slightly deleterious mutations because purifying selection is less important than genetic drift. These mutations, known as drift load, have received very little attention in empirical work, even though they may be important in explaining population and species persistence.

Project of Yvonne Willi



Willi Y, Griffin P, Van Buskirk J (2013) Drift load in populations of small size and low density. Heredity 110:296–302

Willi Y (2013) Mutational meltdown in selfing Arabidopsis lyrata. Evolution 67:806–815