Information on genetic variation in a population is useful to develop plans for sustainable management. Mitochondrial cytochrome b (Cyt b) gene sequence analysis has been found to be a powerful tool for assessing intraspecific genetic diversity of fish and other animals. We analyzed the partial sequences of the Cyt b gene of introduced and hatchery-bred Thai and Viet Nam P. hypophthalmus and indigenous wild Pangasius pangasius from Bangladesh We detected a low level of genetic diversity in the Thai pangasius compared to the Viet Nam pangasius as far as haplotype and nucleotide diversities are concerned. On the other hand, we observed a high level of haplotype and nucleotide diversity in Bangladesh pangasius. The population differentiation statistic (F_ST) between Bangladesh-Thai, Bangladesh-Viet Nam and Thai-Viet Nam population pairs were significant. The present study revealed that the Thai pangasius population experienced expansion in recent past while the Bangladesh and Viet Nam pangasius populations might be either subdivided or have passed through a population bottleneck. Our results can be used to guide brood stock management in these populations.

有关人口遗传变异的信息对于制定可持续管理计划很有用。线粒体细胞色素b（Cyt b）基因序列分析已被发现是评估鱼类和其他动物种内遗传多样性的有力工具。我们分析了引进的和孵化的泰国和越南P. hypophthalmus和本地野生Panggasius pangasius的Cyt b基因的部分序列来自孟加拉国就单体型和核苷酸多样性而言，我们发现泰国pangasius的遗传多样性水平低于越南pangasius。另一方面，我们观察到孟加拉孟加拉虎的单倍型和核苷酸多样性较高。孟加拉-泰国，孟加拉-越南和泰国-越南人口对之间的人口分化统计（F _ST）很重要。目前的研究表明，泰国的pangasius人口在最近几年经历了扩张，而孟加拉国和越南的pangasius人口可能被细分，或者已经经历了人口瓶颈。我们的结果可用于指导这些人群的亲鱼种群管理。