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目的阐明我国中华白蛉群体的遗传差异,探讨四川白蛉的分类地位。方法在我国陕西、河南、甘肃和四川等地采集白蛉,依据形态和分子特征鉴别种类,扩增其线粒体DNA细胞色素b(mitochondrial DNA cytochrome b,mt DNA-Cytb)基因片段,测定和分析序列。结果共获得42个单倍型,形成2个独立的家系,存在明显的地理聚集性,分别是来自陕西和河南的各单倍型家系,以及四川和甘肃的单倍型家系,均呈平行演化,四川白蛉与中华白蛉的单倍型未完全区分。分子变异等级分析(analysis of molecular variance,AMOVA)计算结果显示变异主要存在于种内群体间(89.25%),其次是群体内个体间(20.41%),种间的变异部分为负值,FST值为0.808,各群体间具有相当水平的遗传分化。各群体间的地理距离与基因流的相关性Mantel检验,显示两者呈负相关性(R2=0.888),群体遗传结构符合距离隔离模型。结论我国中华白蛉群体间遗传差异大小与地理距离存在密切相关性,综合分析显示中华白蛉与四川白蛉在形态和分子水平已出现遗传分化,支持其为独立种。
Objective To elucidate the genetic differences of Chinese white catfish and discuss the taxonomic status of white catfish in Sichuan Province. Methods The Chinese white shoots were collected from Shaanxi, Henan, Gansu and Sichuan provinces in China. The species were identified according to their morphological and molecular characteristics. The mitochondrial DNA cytochrome b (mt DNA-Cytb) gene fragment was amplified and sequenced . Results A total of 42 haplotypes were found, forming two independent families with obvious geographic clustering, which were haplogroups from Shaanxi and Henan, and haplogroups from Sichuan and Gansu respectively. , Haplotypes of Sichuan white catfish and Chinese catfish are not completely distinguished. The results of analysis of molecular variance (AMOVA) showed that the variation mainly existed in the intraspecies (89.25%), followed by individuals (20.41%) in the individuals. The variation between species was negative and the FST value 0.808, with a significant level of genetic differentiation among the groups. The Mantel test showed that there was a negative correlation between the geographical distance and the gene flow (R2 = 0.888). The population genetic structure was in line with the distance isolation model. Conclusion There is a close relationship between the size of genetic divergence and the geographic distance in Chinese white catfish. The comprehensive analysis showed that the genetic diversity of Chinese white catfish and white catfish appeared in the morphological and molecular level, supporting their independence.