长江流域3个群体草鱼mtDNAD-loop区段的PCR-RFLP分析

PCR-rflp Analysis on mtDNA D-loop Region of Three Populations of Grass Carp(Ctenopharyngodon idellus)in Yantze River

对采自长江流域湖北省监利县、江西省九江市以及江苏省扬州市邗江区3个群体的141尾草鱼线粒体 DNA 的 D-loop 区段进行 PCR 扩增,使用12种核酸内切限制酶酶切.结果显示,扩增出的140尾试验鱼的mtDNA D-loop 区段长度约为1.6kbp,监利群体中的1尾约为1.8kbp,个体间存在长度变异现象;6种限制酶具有酶切位点,共检测到两种单倍型,其中监利群体中有长度变异的1尾为一种单倍型,另外140尾为另一种单倍型.依据单倍型频率的组成情况计算出九江和邗江两群体内的单倍型多样性指数、核苷酸多样性指数均为0,监利群体内的分别为0.0466、0.00180;监利群体与邗江(或九江)群体间的 Rogers 遗传距离为0.0403;x^2检验结果显示3个群体间的遗传差异不显著(P>0.05).这些结果表明草鱼 mtDNA D-loop 区段的遗传多样性很低.

The D-loop region on the mitochondrial DNA of 141 grass carps （Ctenopharyngodon idellus） from three populations was PCR-amplified and surveyed by 12 restriction endonucleases. The samples were collected from different regions of Yantze River （Jianli county in Hubei Province; Jiujiang city in Jiangxi Province; Hanjiang borough in Yangzhou city of Jiangsu Province）. The results showed that the lengths of the D-loop regions amplified in 140 samples were about 1.6 kbp, while the D-loop region of one sample in the Jianli population was about 1.8 kbp long, which revealed the length variation. Restriction sites were observed with 6 different kinds of enzymes, and 2 haplotypes were detected. Only one sample has length variation belongs to one haplotype, while the remaining 140 samples belong to the other. Based on the haplotype frequencies, the haplotype diversity index and nucleotide diversity index within the Jiujiang and the Hanjiang populations were both 0, but they were 0. 0466 and 0. 00180 within Jianli population. The Rogers＇ distance between the Jianli population and the Jiujiang （or Hanjiang） population was 0. 0403. The X^2 test showed that there was no significant variance among the three populations （P〉0. 05）. As a result, the genetic diversity in the mtDNA D-loop region of grass carps was quite low.