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Genetic
diversity in Japanese chiton, Acanthopleura
japonica
|
SASAKI
M., HAMAGUCHI M.
and OKOSHI
K. |
The
Japanese chiton, Acanthopleura
japonica distributes widely along the coast of Japan Island
except Hokkaido. We supposed that A.japonica
can be discriminated at least two types by morphological
difference. Especially by the difference of valve pattern, we
call the one is BLACK TYPE (These valve surface were blackish
and they didn’t have clear design), another is MEDAMA TYPE. (MEDAMA
means eye. They had two black spots like eyes in each shell
plate.) In order to compare both heredity diversity, when we
analyzed partial nucleotide sequence of the mitochondrial
cytochrome oxidase subunit I (COI) gene, the homology between
BLACK and MEDAMA was 90~92%. But in proportion to more
investigation, we found one more type which form resembled BLACK
TYPE, although both homology was 94~95%. (They were found at
first in Shiwonomisaki, Wakayama, so we temporarily named them
SHIWO TYPE.)
Since the partial sequence of COI gene had some different
restriction site against FokI digestion for every type, each
could be distinguished clearly.
Then we collected chitons in several coasts of Kushimoto-cho,
Wakayama where three types of A.japonica
lived nearby and we investigated each feature in the habitation
environment. The discrimination of A.japonica
was performed morphologically and genetically. And we studied
about the correlation between the dominant type and the effect
of the tide and the topography at an every points.
As
a result, the BLACK TYPE dominated near the strait, which had a
rapid flow of tide comparatively and the MEDAMA TYPE tended to
dominate at the inner bey, which touched Honshu and lapped wave
calmly. On the other hand, most SHIWO TYPE inhabited the tip of
cape, which faced open sea and lashed strong wave |
