都柳江粗唇种群线粒体DNA Cyt b基因和D-loop序列组成及遗传多样性

以采自都柳江40尾粗唇(Leiocassis crassilabris)个体为样品,采用PCR和DNA测序技术对粗唇都柳江种群Cyt b基因和D-loop序列进行了分析。获得了长度分别为1 118 bp、776~778 bp的粗唇Cyt b基因、Dloop序列。2段序列的碱基组成均为A+T的含量高于G+C的含量,但Cyt b基因碱基变异率(0.27%)显著低于D-loop的碱基变异率(3.34%~3.35%)。对粗唇D-loop序列结构进行了分析,识别了其终止序列区、中央保守区和保守序列区等的特征序列。都柳江粗唇40个个体Cyt b基因、D-loop序列中分别有3、20个多态位点,分别定义了4、10种单倍型。都柳江粗唇种群Cyt b基因和D-loop序列的单倍型多样性指数、核苷酸多样性指数和平均核苷酸差异数分别为0.146、0.000 13、0.150和0.404、0.003 17、2.444。都柳江粗唇种群遗传多样性较低,开展该种鱼类种群遗传多样性的研究和保护十分必要。

Composition and genetic diversity of mitochondrial DNA Cyt b gene and D-loop sequences in the population of Leiocassis crassilabris from the Duliu River

The sequences of Cyt b gene and D-loop in the species were analyzed using the methods of PCR and DNA se-quencing according to the 40 individuals of L. crassilabris respectively from Dushan, Sandu, Rongjiang and Congjiang a-long the Duliu River. The sequences of 1 118 bp of the Cyt b gene and 776~778 bp of the D-loop were obtained respec-tively, and the quantity proportion of bases A+T in total bases was higher than that of bases G+C in both of the two se-quences but the substitution rate of bases in the sequence of Cyt b gene ( 0. 27%) was obviously less than that of D-loop (3. 34% ~3. 35%) in the population. The characteristic sequences in the extended termination associated sequence, the central conserved domain and the conserved sequence block of D-loop were identified in L. crassilabris. 3 and 20 variable loci were detected as well as 4 and 10 haplotypes were defined respectively for the sequences of Cyt b gene and D-loop in the 40 individuals of L. crassilabris from the Duliu River. The haploidtype diversity, nucleotide diversity and average num-ber of nucleotide differences were 0. 146, 0. 000 13, 0. 150 and 0. 404, 0. 003 17, 2. 444 respectively on the basis of the sequences of Cyt b gene and D-loop in the population. The population of L. crassilabris had low genetic diversity in the Du-liu River now. Therefore, it′s necessary to study and protect the genetic diversity of population of L. crassilabris from the Duliu River.