Spatial genetic structure of clonal and sexual reproduction in a population of Abeliophyllum distichum (Oleaceae), an endangered monotypic genus

抄録

We used allozyme loci, join-count statistics, and Moran's spatial autocorrelation statistics to quantify the spatial genetic structure caused by clonal reproduction from that maintained in sexually reproduced individuals in a population of distylous shrub Abeliophyllum distichum, a monotypic genus endemic to the central Korea. The population harbors high levels of multilocus genotypic diversity (mean D_G = 0.960). Join-count statistics showed that there were statistically significant clustering of clonal genotypes within distances < 6 m. Both the entire population and the set of sexually reproduced individuals exhibited significant spatial autocorrelation up to the scale of about < 10 m, and the sexually reproduced individuals are in a substantially structured, isolation by distance, manner. This indicated that gene flow would not be extensive in a population of A. distichum because of pine forest acting as a shield for wind movement. Probable unequal ratio of the two floral morphos, selfing via matings between clones, and/or consanguineous matings may be factors for decreasing seed sets observed in the populations of the species ("inbreeding depression").
It is recommended that the sampling for conservation purposes might be performed at a diameter of more than 13 m to extract the genetic diversity across an entire population.