30. COMPARATIVE STUDY OF CHROMOSOME VARIATION IN THE JAPANESE AND AMERICAN TRILLIUM SPECIES

• Main Author: 福田 一郎
• Format: Report
• Language: English
• Published: 1974
• Subjects: Pacific; Sakhalin
• Online Access: https://twcu.repo.nii.ac.jp/?action=repository_uri&item_id=23425; http://id.nii.ac.jp/1632/00023419/; https://twcu.repo.nii.ac.jp/?action=repository_action_common_download&item_id=23425&item_no=1&attribute_id=22&file_no=1

The Asian Trillium kamtschaticum is distributed in Tohoku, Hokkaido, Kuril islands and Sakhalin. On the other hand, cross the Pacific Ocean, the American Trillium ovatum occurs in California, Oregon, Washington, Idaho, Montana and British Columbia. Both species are the diploids which have ten somatic chromosomes consisting of two metacentrics, six submetacentrics and two acrocentrics. As the results of population analyses by allocycly, the following subjects were found: 1) In T. kamtschaticum, chromosome A is most variable and chromosome C is the smallest variation but, in T, ovatum, chromosome C has the largest variation and chromosome A is less variable. These largest variations of both species attain 45 per cent of all variations respectively in each species. It is considered that chromosome variations were prompted predominantly by a special kind of chromosome although the kind of chromosome was different in each species. 2) Both species have two or three races within the species: Northern Hokkaido, Southern Hokkaido and Eastern Hokkaido races in T. kamtschaticum, the Pacific Coast and the Rocky Mountain races in T. ovatum. 3) These races are characteristic in the population structure: the heterogeneous population structure, Eastern Hokkaido populations in T. kamtschaticum and the Rocky Mountain populations in T. ovatum, the homogeneous population structure, Northern Hokkaido and Southern Hokkaido populations in T. kamtschaticum and the Pacific Coast populations in T. ovatum. It seems that the same pattern of speciation has been advancing in the Asian and American regions.