利用Cyt b基因序列探讨柴达木裸裂尻鱼的分类学地位

Taxonomic Status of Schizopygopsis kessleri Inferred from Cyt b Gene Sequence

长期以来,柴达木裸裂尻鱼(Schizopygopsis kessleri)的分类学地位存在争议。为此,测定了柴达木裸裂尻鱼格尔木河及托素湖种群24个个体及黄河裸裂尻鱼(S.pylzovi)黄河及大通北川河种群12个个体的Cytb基因全序列。通过遗传距离和系统发育分析,探讨了柴达木裸裂尻鱼的分类学地位。结果显示,柴达木裸裂尻鱼与黄河裸裂尻鱼在系统进化树上并未形成相应的单系群;柴达木裸裂尻鱼与黄河裸裂尻鱼种间平均遗传距离为0.54%,明显低于裂腹鱼亚科其他属鱼类的种间遗传距离及本属其他种间遗传距离,表明来自柴达木盆地格尔木河和托素湖的裸裂尻鱼与黄河裸裂尻鱼之间没有达到种级水平的显著分化。综合地质学资料和柴达木水系与黄河水系现今的隔离格局,建议将柴达木裸裂尻鱼作为黄河裸裂尻鱼的一个亚种,即S.pylzovi kessleri。

The taxonomic status of Schizopygopsis kessleri distributed in Qiadam Basin is remained controversial for a long time. In the present study, the complete sequence of the mitochondrial Cyt b gene from twenty four individuals of S. kessleri collected from the Geermu River and Tuosu Lake in Qiadam Basin and twelve individuals of S. pylzovi from the Yellow River and Beichuan River in Datong was sequenced. The taxonomic status of S. kessleri was investigated based on the genetic distance and phylogenetie analyses. The results showed that individuals of S. kessleri and S. pylzovi were not formed reciprocal monophyIetic elades in the ph：ylogenetic trees, and the average genetic distance （0.54%） between S. kessleri and S. pylzovi was lower than that between other species from the same genus and between species from other genera of subfamily Schizothoraeinae, which suggested that S. kessleri from Qiadam Basin has not reached the genetic divergence level of species. The results of previous geological study, coupled with the status of geographical isolation between Qiadam Basin and Yellow River, suggested that S. kessleri should be regarded as a subspecies, S. pylzovi kessleri of S. pylzovi .