title: Temporal aspects of the fine-scale genetic structure in a population of Cinnamomum insularimontanum (Lauraceae).
abstract: Cinnamomum insularimontanum Hayata (Lauraceae) is an insect-pollinated, broad-leaved evergreen tree with bird-dispersed seeds. We used allozyme loci, Wright's fixation index, spatial autocorrelation statistics (Moran's I), and coancestry measures to examine changes in genetic structure among four age-classes within a recently founded study population (60 x 100 m area) in southern Korea. There were no significant differences in expected heterozygosity among age classes. However, significant genetic differentiation among age classes was detected (P<0.0001). Fixation indices within age classes showed significant deficits of observed heterozygosity, which may be caused by partial selfing. The homogeneity of genetic structure among four age-classes may reflect similar spatial patterns of seed immigration from surrounding populations occurring year after year. Finally, the average Moran's I and coancestry estimates indicated essentially random spatial distributions of alleles for each of the four age-classes and between seedlings and 2-4 year juveniles vs adult trees. These findings are very similar to those observed in the same study area for another member of the Lauraceae, Neolitsea sericea, which has a very similar life history and ecological characteristics (ie, bird-dispersed fruits, insect pollination, and a similar age structure). Together, these results suggest that the fleshy drupes of lauraceous species represent an adaptation to aid in the independent dispersal of seed by birds, which in turn may increase the genetic diversity of founders colonizing new habitats.
authors.affiliation: Department of Biology, Gyeongsang National University, Jinju, Republic of Korea.
authors.forename: M Y
authors.initials: MY
authors.lastname: Chung
authors.forename: J D
authors.initials: JD
authors.lastname: Nason
authors.forename: B K
authors.initials: BK
authors.lastname: Epperson
authors.forename: M G
authors.initials: MG
authors.lastname: Chung
mesh_terms: D005075:Biological Evolution; D027424:Cinnamomum / Q000235:genetics*; D004798:Enzymes / Q000235:genetics; D005828:Genetics, Population; D011110:Polymorphism, Genetic; D013997:Time Factors
chemical_list: D004798:Enzymes