新疆3种雅罗鱼线粒体DNA细胞色素b序列的差异与系统进化

Divergence and Systematical Evolution of Three Leuciscus Species in Xinjiang: Mitochondrial DNA Cytochrome b Sequences

利用鲤科鱼类线粒体DNA细胞色素b通用引物对分布在新疆的准噶尔雅罗鱼(Leuciscusmerzbacheri)、贝加尔雅罗鱼(L .baicalensis)和高体雅罗鱼(L .idus) 3个鱼种共1 5尾个体的线粒体DNACytb部分核苷酸序列进行了测定,获得1 5条长度为41 3bp的同源基因序列。同源基因序列分析显示,在3种雅罗鱼1 5条mtDNACytb基因片段中,A、T、C、G碱基的平均含量分别是:2 7 4%、2 6 7%、1 7 2 %、2 8 7% ,其中A+T含量(5 4 1 % )高于G +C含量(4 5 9% ) ;共检测到5 2个突变位点;转换比颠换发生频率高,转换颠换比值(R)是3 5。mtDNACytb的进化速率在3种雅罗鱼间表现出不一致性,贝加尔与高体雅罗鱼、贝加尔与准噶尔雅罗鱼种间遗传距离分别是0 1 2 5 1和0 1 2 61 ,保守性较低;高体与准噶尔雅罗鱼种间的遗传距离是0 0 0 0 7,高度保守。mtDNACytb分子系统树显示,在3种雅罗鱼中贝加尔雅罗鱼独立成一枝,高体雅罗鱼和准噶尔雅罗鱼聚成一类。提示了,在mtDNACytb分子水平上,高体雅罗鱼和准噶尔雅罗鱼的亲缘关系十分相近,贝加尔雅罗鱼与准噶尔雅罗鱼的亲缘关系相距较远。我们对准噶尔、贝加尔和高体雅罗鱼mtDNACytb方面的研究与陈星玉对其骨骼类型的研究结果相吻合。

Using the general primers in mtDNA cyt b of Cyprinidae fish, we examined partial nucleotide sequences of fish mitochondria DNA (mtDNA) cytochrome b region from Leuciscus merzbacheri, L. baicalensis and L. idus in Xinjiang, China. We sequenced 413 bp lengths of homological fragments in the cyt b from 15 individuals of the three fish species. The homological fragment analysis showed that the average content of A,T,C,G were 27.4%,26.7%, 17.2%, and 28.7%, respectively, and A+T content (54.1%) was higher than G+C content (45.9%). A total of 52 mutation spots were tested in 413 homological nucleotides. Transition was higher than transversion, and the ratio between transition and transversion was 3.5. The evolution speed of mtDNA cyt b manifests non-identity among three Leuciscus. Between L. baicalensis and L. idus, L. baicalensis and L.merzbacheri, the genetic distances were 0.125 1 and 0.126 1, respectively, and there were low conservation. The genetic distance between L. idus and L.merzbacheri was 0.000 7, and there was very high conservation. The phylogenetic tree of mtDNA cyt b built with MEGA 2.1 showed that L. baicalensis was an independent one, and L. idus and L.merzbacheri were closer. It is suggested that the relationship between L. idus and L.merzbacheri is close, and that between L. baicalensis and L. merzbacheri is far.