Genetic diversity in the Japanese rosy bitterling, Rhodeus ocellatus
kurumeus (Cyprinidae)
Kouichi Kawamurall Yoshikazu Nagata,
Hiroyuki Ohtaka Yoshihiko Kanoh and Jyun-ichi Kitamura
(2001) Ichthyol Res
48: 369-378
Abstract
Comparison of meristic characters (pored lateral line scales,
vertebrae, and fin rays), and PCR-RFLP analysis in the D-loop and ND1 regions of
mitochondrial DNA were performed to estimate the genetic diversity in local
populations of the Japanese rosy bitterling, Rhodeus ocellatus kunimeus.
In terms of meristic characters, the Fukuoka population was the largest in both
range and variance of the number of pored lateral line scales and vertebrae
(abdominal and caudal), and Osaka was the second, whereas the Kagawa population
showed the smallest range and variance in these characters. In PCR-RFLP
analysis, 11 haplotypes (3 in Fukuoka, 2 in Okayama, 2 in Kagawa, and 4 in
Osaka) were observed, and nucleotide sequence divergence (NSD) was approximately
two times larger in ND1 (mean, 0.61%) than in D-loop (mean, 0.31%). In the
neighbor-joining (NJ) tree, based upon the NSD value in ND1, haplotypes were
arranged into four clades, which corresponded to the locality of each haplotype.
The Fukuoka population was conspicuously apart from the other populations (mean.
0.90%in NSD), but the remaining three showed a similar genetic distance with
each other (mean, 0.48%-0.52% in NSD). In haplotype diversity of mtDNA, half the
stations in Osaka and all in Kagawa were monomorphic. Especially, two haplotypes
endemic to Kagawa were randomly distributed, irrespective of drainages.
Rhodeus o. kurumeus in Fukuoka inhabits small rivers and creeks (open
water systems), while that in Kagawa and Osaka lives in small ponds (closed
water systems). Taking the information of morphology, mtDNA, and habitat into
consideration, the low genetic diversity in Kagawa and Osaka populations of
R. o. kurumeus is thought to be mainly the result of the isolation of
their habitat.