In the present study, thirty-six individuals of Acheilognathus macropterus were collected from the Heilongjiang River, the Changjiang River, and the Nandujiang River. Partial mitochondrial cytochrome b gene region(636 base pair) was sequenced to these samples and 22 haplotypes were found. With A. chankaensis and A. tokinensis as outgroups, their relationships were analyzed. The p-distances were calculated with Mega software, and molecular phylogene-tic tree was constructed using the neighbor-joining(NJ) method. proportions of main morphological characters were compared as well. P-distances showed that the genetic differences in A. macropterus samples were much smaller than those between these samples and the outgroups. Molecular phylogenetic tree showed that samples with barbels and those without barbels were intermingled There was no distinct difference in proportions of morphological characters. The results Suggested that samples with barbels and those without barbels( formally identified as A. taenianalis) are the same species, A. taenianalis is a junior synonyms of A. macropterus. The thirty-six individuals were grouped into 5clades. and the positions of the samples in the clades were corresponded with their geographical distributions. Among the 5 clades, clade I and clade 5 included specimens from Heilongjiang River and Nandujiang River respectively. The specimens from Changjiang River scattered into clades 2, 3, and 4, and there were distinct genetic differences (>5%) among them. Interestingly, the distributions of the 21 samples in these three clades were not correlated to their geographical distributions. It is postulated that these genetic differences were due to bitterling's mate choice, the prozygotic isolation. The genetic differences between the I ish front Nandujiang River and those from the mainland indicated the), were separated early. However, the small genetic differences among the samples and their positions of the fish from Heilongjiang River in the molecular phylogenetic tree indicate that fish front Heilongjiang River might disperse from Changjiang River very late.
Zhu Yu-Rong; Liu Huan-Zhang (email@example.com).Genetic diversity and biogeographical process of Acheilognathus macropterus revealed by sequence variations of mitochondrial cytochrome b gene,Acta Hydrobiologica Sinica,2006,30(2):134-140