青蛤两个异域种群的遗传多样性与分化研究

STUDIES ON GENETIC DIVERSITY AND DIFFERENTIATION BETWEEN TWO ALLOPATRIC POPULATIONS OF CYCLINA SINENSIS

利用RAPD技术对分布于中国辽宁庄河(LZ)及广东惠东(GH)的两个青蛤(Cyclinasinensis)野生种群遗传多样性及其遗传分化进行了分析。22个10碱基引物从两个种群分别扩增到179和181条扩增谱带,全部扩增片段长度在210—2850bp之间。根据扩增结果计算出两个种群的多态位点比例(P)分别为76.92%和81.31%,平均杂合度(H)分别为0.2815和0.3012。两种群间遗传距离(D)和近交系数(Fst)分别达到0.103及0.1997,结果表明两个异域种群不但遗传多态性较高,而且出现了明显的种群分化现象。文章还初步讨论了青蛤种群分化的机制、遗传结构与异地引种关系等问题。

The Cyclina sinensis(Gmelin)is a important species for marinculture intensive exploitation of the State Tenth five-years plan due to their commercial value of fishery industry and their widely distributing of seashore in China. The paper preliminary discussed genetic diversity and genetic differentiation of wild Cyclina sinensis populations distributed in Zhuanghe Liaoning province(LZ)and Huidong Guangdong province(GH)areas,the physical geographic conditions including latirude、climate and temperature of habitat are much different between two populations of Cyclina sinensis,the annual temperature of the former area,for instant,is 12.6 centigrade lower than that of later,and the latitude of the former area is 16.98 higher than later. In the present study were investigated using the random amplified polymorphic DNA(RAPD)technique to detect the genetic variation and genetic differentiation of two populations. A total of 22 ten-base primers were applied in the RAPD analysis,179 and 181 fragments ranging from 210 to 2850 bp were amplified from the above two populations respectively. The primer yielded different pattern in terms of length and intensity of amplifications fragments. There were 24 species-special and 2 population-special bands were amplified by the 22 primers from 40 individuals of two populations. After using the TFPGA(Tools For Population Genetic Analyses)package designed by Mark P. Miller(1999)to figure out the proportions of polymorphic amplified fragments(P)and value of Average Heterozygosity(H)were 76.92%,81.31%and 0.2815,0.3012 respectively. The genetic distance(D)and inbreeding index(Fst)between the two wild populations were 0.103 and 0.1997 respectively. The RAPD analysis revealed that the genetic diversity was remarkably high for each group and the population differentiation of Cyclina sinensis was significant. The genetic differentiation of the populations and the seed introduction of this species were also discussed in this paper.