Clonal and spatial genetic structure in Eurya emarginata (Theaceae)

Eurya emarginata (Thunb.) Makino (Theaceae) is a dioecious, insect-pollinat ed tree, which combines sexual reproduction and clonal spread. It is narrow ly distributed in coastal areas from southern China, along southern Korea, and extending to central and southern Japan. We used allozyme loci and spat ial autocorrelation statistics to examine the clonal structure and the spat ial distribution of allozyme polymorphisms of sexually reproduced individua ls in a study population (70 m x 120 m area) in Korea. The population maint ains moderate levels of allozyme variability (mean H-e = 0.133), and multil ocus genotypic diversity is high (mean D-G = 0.992). The frequency of clone s was 0.377 (90/239), and the mean clone-pair distance was very large (35.0 6 m +/- 1.91 m [SE]), indicating that clones can form at long distances awa y 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 u nlike joins showed that, contrary to expectation for such species, clonal r eproduction does not contribute substantially to genetic isolation by dista nce neither among the sexually reproduced individuals nor the whole populat ion. In contrast, limits to seed and pollen dispersal create substantial le vels of genetic structure.