scholarly journals Epistasis, inbreeding depression, and the evolution of self‐fertilization

Evolution ◽  
2020 ◽  
Vol 74 (7) ◽  
pp. 1301-1320
Author(s):  
Diala Abu Awad ◽  
Denis Roze
Keyword(s):  
Inbreeding Depression ◽  
Self Fertilization

Single Gene Control of Postzygotic Self-Incompatibility in Poke Milkweed, Asclepias exaltata L.

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 893-907
Author(s):  
Sara R Lipow ◽  
Robert Wyatt
Keyword(s):  
Inbreeding Depression ◽  
Single Gene ◽  
Diallel Cross ◽  
Gene Control ◽  
Self Incompatibility ◽  
S Locus ◽  
Fertile Plant ◽  
Diallel Crosses ◽  
Prezygotic Barriers ◽  
Self Fertilization

Abstract Most individuals of Asclepias exaltata are self-sterile, but all plants lack prezygotic barriers to self-fertilization. To determine whether postzygotic rejection of self-fertilized ovules is due to late-acting self-incompatibility or to extreme, early acting inbreeding depression, we performed three diallel crosses among self-sterile plants related as full-sibs. The full-sibs segregated into four compatibility classes, suggesting that late acting self-incompatibility is controlled by a single gene (S-locus). Crosses between plants sharing one or both alleles at the S-locus are incompatible. An additional diallel cross was done among full-sib progeny from a cross of a self-sterile and a self-fertile plant. These progeny grouped into two compatibility classes, and plants within classes displayed varying levels of self-fertility. This suggests that the occasional self-fertility documented in natural pollinations is caused by pseudo-self-fertility alleles that alter the functioning of the S-locus.

scholarly journals The role of self-incompatibility systems in the prevention of bi-parental inbreeding

2017 ◽  
Author(s):  
Tara N Furstenau ◽  
Reed A Cartwright
Keyword(s):  
Inbreeding Depression ◽  
Pollen Dispersal ◽  
Dispersal Distance ◽  
Inbreeding Avoidance ◽  
Self Incompatibility ◽  
Plant Populations ◽  
Population Sizes ◽  
Self Fertilization ◽  
Individual Based Simulation

Hermaphroditic plants experience inbreeding through both self-fertilization and bi-parental inbreeding. Therefore, many plant species have evolved either heteromorphic (morphology-based) or homomorphic (molecular-based) self-incompatibility (SI) systems. These SI systems limit extreme inbreeding through self-fertilization and, in the case of homomorphic SI systems, have the potential to limit bi-parental inbreeding, which is common when dispersal is restricted to a local region. Homomorphic SI species are prevalent across the angiosperms, and it is often assumed that the potential to reduce bi-parental inbreeding may be a factor in their success. To test this assumption, we developed a spatially-explicit, individual-based simulation of plant populations with either heteromorphic SI or one of three different types of homomorphic SI. In our simulations, we varied dispersal distance and the presence of inbreeding depression. We found that autozygosity in the homomorphic SI populations was significantly lower than in the heteromorphic SI populations and that this reduction was due to bi-parental inbreeding avoidance. As expected, the differences between the homomorphic and heteromorphic SI populations were more pronounced when seed and pollen dispersal was limited. However, levels of homozygosity and inbreeding depression between these plant populations were not different. At low dispersal, homomorphic SI populations also suffered reduced female fecundity and had smaller census population sizes. Our results suggest that bi-parental inbreeding avoidance was unlikely to be a major driver in the evolution of homomorphic SI systems.

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