Pedigree-based inbreeding: Self-incompatibility reduction of inbreeding is highly localisedwithin the genome

Description

Inbreeding has a complex relationship to population pedigree structure. On the one hand, selfing or mating between close relatives has an immediate impact on autozygosity, on the other mating with a finite population results in a gradual increase in autozygosity across the whole population. Self-incompatibility (SI) in plants is widely regarded as a mechanism to reduce offspring autozygosity. In order to investigate the impact of SI on population inbreeding, we calculated pedigree-based inbreeding coefficients in simulated populations exhibiting a range of contrasting breeding systems: dioecious, gynodioecious, random mating, gametophytic SI, and sporophytic SI. For each mating system, we conducted 200 simulations across a range of population sizes from 50 to 3000. We examined the autozygosity across individuals in each generation at the SI locus and at loci of increasing map distance from the SI locus up to 55 centimorgans. We found that autozygosity was maintained at low levels in the immediate genetic map vicinity of the SI locus, but that autozygosity approached levels found under random mating by the time loci were over 30 centimorgans away. Our conclusion is that effects of SI on levels of inbreeding are highly localised within the genome to loci that are closely linked to the SI locus. Thus, SI prevents inbreeding locally but has limited if any impact across the whole genome, which challenges long-standing perceptions of the biological role of SI in plants.

Period	22 Jun 2019
Event title	Society for the Study of Evolution: 2019 annual meeting
Event type	Conference
Location	Providence, United States, Rhode IslandShow on map
Degree of Recognition	International