Movement and dispersal of marine nematodes living in the interstitial space of sand

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11833006
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Institution: KYOTO UNIVERSITY
• Principal Investigator: SHIRAYAMA Yoshihisa Kyoto University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (60171055)
• Co-Investigator(Kenkyū-buntansha): WADA Hiroshi Kyoto University, Graduate School of Science, Assistant, 大学院・理学研究科, 助手 (60303806)
• Project Period (FY): 1999 – 2000
• Keywords: Nematodes / Geographic Isolation / Gene Flour / Tanabe Bay / Meyersia

Research Abstract

The purpose of the present study is to clarify the difference of isolated two population of marine nematodes Meyersia japonica population established at two subtidal areas in Tanabe Bay, i.e. north shore of the Seto Marine Biological Laboratory, Kyoto University and south shore of Hatake jima island, from the points of view of morphology and molecular biology. In 1999, Meyersia japonica individuals were collected from the former site, and we established method for RAPD analysis. However, population of the species in Hatake jima was not found. In 2000, thus, an extensive survey of the species was carried out around the island, and population of Meyersia japonica finally was found from unknown place. Sampling was done in August 2000 at both sites. Using the material, morphology of body shape, e.g. tail length and teeth in the stoma were analyzed. To do the analysis, light microscopic image was recorded using digital camera, and measurement was done using image analyzing program. As a result, no statistically significant difference was found between two populations in all measured items. For molecular RAPD analysis, 19 primers were used, and 5 of them had more than two bands. A total of 33 polymorphic bands were detected, but only 1.13 % of them were the variation among populations, and no significant genetic difference was observed. These results suggest that though the animal has little ability of dispersal, there is a flow of gene between two geographically isolated Meyersia japonica populations. Though typhoon seems to play an important role for this genetic flow, we could not study its affect because no typhoon approached to Tanabe Bay during the study period.