Geographic distribution of Pelteobagrus fulvidraco and Pelteobagrus vachelli in the Yangtze River based on mitochondrial DNA markers.

Three populations of Pelteobagrus vachelli and Pelteobagrus fulvidraco of the Yangtze River were examined by PCR-RFLP analysis of mitochondrial DNA fragments. ND5/6 and D-loop fragments were digested by 10 restriction endonucleases. Significant geographic variations between upstream and mid-downstream populations in the haplotype frequencies and restriction patterns were revealed. This suggested that the diversity of P. vachelli was high; 11 haplotypes were obtained from all the samples. The upstream population shared seven haplotypes and the middle and downstream populations shared another four haplotypes. Among all of the haplotypes, one haplotype was shared in 30 samples of the populations from middle and downstream, but it was not found in the upstream population. Any haplotype found in the upstream population was not detected in the middle and downstream populations. Genetic diversity of P. fulvidraco was low and only five haplotyes were detected from all 60 samples. Phylogenic relationships also indicated that the fishes from upstream and mid-downstream were apparently divided into two populations.