Systematics Section / ASPT
Takayama, Koji , Kajita, Tadashi , Murata, Jin , Yoichi, Tateishi .
Phylogeography and genetic structure of Hibiscus tiliaceus L. (Malvaceae), a pantropical plant with sea-drifted seeds.
GENETIC differentiation and structure were studied in a pantropical plant with sea-drifted seeds, H. tiliaceus L., and the four satellite species. Six microsatellite markers that can detect high levels of allelic diversity were employed to estimate population genetic parameters. In the pair-wise comparisons of species, the five species showed various levels of differentiation. Distinct differentiations were recognized between H. tiliaceus and H. pernambucensis Arruda in the pair-wise comparisons of populations using FST and RST values. In the neighbor-joining tree based on DA distances, in addition, major clusters were predominantly consisted of populations of each species. As the two species showed clear genetic difference in the nuclear DNA marker, the presence of cpDNA haplotype widely shared by populations of H. tiliaceus and H. pernambucensis in the Atlantic Ocean area (Takayama et al. 2006) can be considered as the result of introgression. Lack of genetic differentiation among the populations of H. tiliaceus in the Pacific and Indian Ocean regions was observed, which would suggest that substantial gene flow occurred among populations of these oceanic regions. On the other hand, remarkable genetic differentiation was detected for populations of H. tiliaceus between West Africa and the other areas. The pair-wise comparisons of FST and RST values were generally compared with the level that was recognized between different species examined in this study. This might suggest that they were on the way of marginal speciation. The high level of genetic differentiation at the geographically isolated population of H. tiliaceus is considered as an incipient speciation of satellite species.
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1 - Chiba University, Department of Biology, Faculty Of Science, 1-33 Yayoi-Cho, Inage-Ku, Chiba, 263-8522, Japan
2 - University of Tokyo, Botanical Gardens, 3-7-1 Hakusan Bunkyo-Ku, Tokyo, 112-0001, Japan
3 - University of the Ryukyus, Faculty of Education, 1 Senbaru, Nishihara, Okinawa, 903-0129, Japan
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM