 In this study, researchers examined the effects of selfing and mating type loci on the maintenance of deleterious mutations. They found that selfing can increase the purging time of deleterious mutations, but that the presence of a mating type locus can reduce the purging time and increase the probability of survival of the mutation. Additionally, they observed that rare events of deleterious mutation maintenance can occur, suggesting that deleterious mutations can accumulate near mating type loci over evolutionary timescales. This article was authored by Tazinas, Emily, Jiru, Tatiana, Weber, Amundine, and others.