Clonal and spatial genetic structure in Eurya emarginata (Theaceae)

Eurya emarginata (Thunb.) Makino (Theaceae) is a dioecious, insect-pollinated tree, which combines sexual reproduction and clonal spread. It is narrowly distributed in coastal areas from southern China, along southern Korea, and extending to central and southern Japan. We used allozyme loci and spatial autocorrelation statistics to examine the clonal structure and the spatial distribution of allozyme polymorphisms of sexually reproduced individuals in a study population (70 m x 120 m area) in Korea. The population maintains moderate levels of allozyme variability (mean H-e = 0.133), and multilocus genotypic diversity is high (mean D-G = 0.992). The frequency of clones was 0.377 (90/239), and the mean clone-pair distance was very large (35.06 m +/- 1.91 m [SE]), indicating that clones can form at long distances away from their ancestors. In addition, it was found that genetic patch width was at least 24 m. However, join-count statistics for the total number of unlike joins showed that, contrary to expectation for such species, clonal reproduction does not contribute substantially to genetic isolation by distance neither among the sexually reproduced individuals nor the whole population. In contrast, limits to seed and pollen dispersal create substantial levels of genetic structure.