怒江濒危鱼类角鱼种群遗传结构研究

Population genetic structure of the endangered species Epalzeorhynchus bicornis in the Nujiang River

测定了怒江角鱼(Epalzeorhynchus bicornis)4个群体共70尾个体的线粒体DNA cytb基因序列,以探讨种群遗传结构和遗传多样性。结果显示:1140 bp的cytb基因共检测到13个变异位点,70个样本得到16个单倍型,平均单倍型多样性(h)为0.579,核苷酸多样性(π)为0.00070,遗传多样性表现为较低。木城群体和泸水群体之间的遗传距离最远0.00080,泸水群体和道街群体之间的遗传距离最近为0.00059。Fu′Fs中性检验和碱基岐点分布分析暗示了角鱼在历史上曾经历过遗传瓶颈和种群扩张。分子方差分析(AMOVA)表明,群体间总遗传分化系数Fst=0.0049(P>0.05),几乎所有变异均来自于群体内,群体间未出现遗传分化,提示群体内存在广泛的基因交流。

The mitochondrial DNA （mtDNA） cytochrome b genes of Epalzeorhyrtchs bicornis of total 70 individuals collected from four sites （populations） in Nujiang River were amplified by means of polymerase chain reaction （PCR） and sequenced to test the population genetic structure and genetic diversity. The results showed that 13 variable sites were dete ted in the aligned sequences of 1140 bp, and 16 haplotypes were recoverd among the specimens. The global haplotype diversity （h） and nueleotide diversity （π） were 0. 579 and 0. 00070, respectively. The genetic diversity was low. The genetic distance between KS and MC displayed the highest, up to 0. 00080, while that between KS and DJ was the lowest to 0. 00059. The neutral test of Fu＇Fs indicated gentie bottleneck ang population expansion in history. The fixation indices （ Fst ） of analysis of molecular variance （AMOVA） among populations was 0. 0049 （ P 〉 0. 05 ） , which showed no significant population structure and suggested that there existed strong gene flow.