白洋淀流域宽鳍鱲遗传多样性及种群历史动态

Genetic diversity and population historical dynamics of Zacco platypus in Baiyangdian Basin

基于线粒体Cytb和COI基因联合对白洋淀流域沙河和拒马河宽鳍鱲种群遗传多样性及种群历史动态进行分析。结果表明:141个样本中检测出45个单倍型,种群间共享单倍型有2个。拒马河种群的单倍型多样性与核苷酸多样性(h=0.712 0,π=0.011 82)均高于沙河种群(h=0.451 4,π=0.003 13)。AMOVA分子方差分析、种群间遗传分化指数(FST)及系统发育树均表明2个种群间未出现明显分化,种群内变异(96.43%)大于种群间变异,种群之间存在较大的基因流(6.745)。中性检验、错配分析显示沙河种群和拒马河种群未经历过种群扩张,贝叶斯天际线点图显示沙河种群保持稳定,拒马河种群在0.004百万年前经历了种群扩张。白洋淀流域宽鳍鱲有效种群在0.175百万年前~0.125百万年前经历种群扩张,后维持稳定。结合单倍型网格图及系统发育树分析,沙河种群经历过奠基者效应。参考鲤科鱼类Cytb基因每百万年0.84%~1.00%的进化速率,2个地理种群的分歧时间为0.089百万年前~0.067百万年前。

Based on the combined sequences of mitochondrial Cytb and COI gene, the genetic diversity and population historical dynamics of Zacco platypus from the Sha River and the Juma River of the Baiyangdian Basin were analyzed. The results showed that 45 haplotypes were detected in 141 samples, and two of them were shared between the two populations. The haplotype diversity and nucleotide diversity of the Juma River(JMH) population(h=0.712 0, π=0.0118 2) were higher than those of the Sha River(SH) population(h=0.451 4, π=0.003 13). The analysis of molecular variance(AMOVA), genetic differentiation index(FST) and phylogenetic tree revealed that there was no obvious genetic differentiation between the two populations. The variation within the population(96.43%) was greater than that between the populations, and there was a large gene flow(6.745) between the two populations. Neutrality test and mismatch analysis showed that the SH population and the JMH population had not experienced population expansion. Bayesian skyline plot(BSP) indicated that the JMH population experienced population expansion before 0.004 million years, and the SH population remained stable. The effective population size of the Baiyangdian Basin experienced population expansion before 0.175 to 0.125 million years, and then remained stable. Combined with haplotype network and phylogenetic tree, the SH population has experienced the founder effect. According to the evolution rate of Cytb gene of Cyprinidae from 0.84% to 1.00% per million years, the divergence time of the two populations is estimated to be 0.089-0.067 million years ago.