刺鲃基于线粒体细胞色素b基因的生物地理学过程

以中华倒刺鲃Spinibarbus sinensis为外类群，研究了不同地理种群刺鲃Spinibarbus calduelli细胞色素b基因序列(1140bp)变异，以探讨其生物地理学过程。结果表明：长江下游水系与珠江水系种群的变异值为1．2％—2．3％，与闽江水系的为2．7％—3．7％，与九龙江水系的为3．1％—4．2％，这些值都远远低于它们与中华倒刺鲃的变异值(13．2％—14．6％)。遗传变异值表明了刺鲃的生物地理学过程，首先是东南沿海的水系同内地的水系发生隔离，然后珠江水系同长江水系隔离，这些变化均发生在第四纪。

BIOGEOGRAPHICAL PROCESS OF SPINIBARBUS CALDWELLI REVEALED BY SEQUENCE VARIATIONS OF MITOCHONDRIAL CYTOCHROME b GENE

Spinibarbus caldwelli(Cyprinidae,Barbine,Spinibarbus)is a kind of small to middle sized fish dwelling in the middle or at the bottom of rivers,widely distributed in Yuanjiang River, Zhujiang River, Jiulongjiang River, Minjiang River, Changjiang River, Hainan and Taiwan. Because of the differences of ecological environments, morphological variations were found among the samples of S. caldwelli from different localities. In the present paper, with Spinibarbus sinensis as the outgroup, the cytochrome b genes(1140)of S. caldwelli specimens from different localities were sequenced to study biogeographical process of this species. Molecular phylogenetic trees were constructed according to the neighbor-joining method and the most parsimony method in Mega 2.0 software. The results showed that variations between samples from Changjiang and Zhujiang rivers, Changjiang and Minjiang rivers, Changjiang and Jiulongjiang rivers,were 1.2%-2.3%,2.7%-3.7%,and 3.1%-4.2% respectively. All these are much lower than the interspecies variations (13.2%-14.6%). These variations and molecular phylogenetic trees indicate that the biogeographical process might be that water systems in southeastern coast region separated from the inland water systems first, then separation between Zhujiang River and Changjiang River occurred,and these events should be in the Quaternary.