Authors conducted pollination experiments and genetic analyses using microsatellite loci for a natural population of a shrub species,Magnolia salicifolia,in a secondary Japanese beech forest in Hakkoda mountains,north...Authors conducted pollination experiments and genetic analyses using microsatellite loci for a natural population of a shrub species,Magnolia salicifolia,in a secondary Japanese beech forest in Hakkoda mountains,northern Japan,to analyze inbreeding and inbreeding depression that involve sexual reproduction and population genetic structure of the species.The pollination experiments revealed that self-fertilization through geitonogamy is possible and that the magnitude of inbreeding depression(δ)at the embryonic stage is substantial(δ=0.42),suggesting that the inbreeding depression due to self-fertilization decreases seed production of the natural population.The genetic analyses showed discrepancy in the level of inbreeding between life history stages:the inbreeding coefficient for the juvenile and adult stage was 0.17 and 0.01,respectively,implying that most of inbred progenies cannot grow to the adult stage in the population,since the cumulative inbreeding depression is severe.These results are consistent with the hypothesis that explains mechanisms causing stable maintenance of severe inbreeding depression in partially inbred populations by focusing on the selective interference among deleterious mutations.It is suggested that some reproductive traits facilitating outcrossing in the species would be attributed to the severe cumulative inbreeding depression.展开更多
基金supported by JSPS KAKENHI(Grant number 18380099).
文摘Authors conducted pollination experiments and genetic analyses using microsatellite loci for a natural population of a shrub species,Magnolia salicifolia,in a secondary Japanese beech forest in Hakkoda mountains,northern Japan,to analyze inbreeding and inbreeding depression that involve sexual reproduction and population genetic structure of the species.The pollination experiments revealed that self-fertilization through geitonogamy is possible and that the magnitude of inbreeding depression(δ)at the embryonic stage is substantial(δ=0.42),suggesting that the inbreeding depression due to self-fertilization decreases seed production of the natural population.The genetic analyses showed discrepancy in the level of inbreeding between life history stages:the inbreeding coefficient for the juvenile and adult stage was 0.17 and 0.01,respectively,implying that most of inbred progenies cannot grow to the adult stage in the population,since the cumulative inbreeding depression is severe.These results are consistent with the hypothesis that explains mechanisms causing stable maintenance of severe inbreeding depression in partially inbred populations by focusing on the selective interference among deleterious mutations.It is suggested that some reproductive traits facilitating outcrossing in the species would be attributed to the severe cumulative inbreeding depression.
