栉孔扇贝不同种群的遗传结构及其杂种优势

STUDIES ON THE GENETIC STRUCTURE OF DIFFERENT POPULATION OF CHLAMYS FARRERI AND THEIR HYBRIDS′ HETEROSIS

采用来自韩国野生的栉孔扇贝和中国养殖的栉孔扇贝以及发病区存活个体作为亲本 ,构建韩国野生×韩国野生、韩国野生×中国养殖、韩国野生×中国养殖发病区存活个体以及中国养殖×中国养殖共 4个交配组合 ,通过对F1 代个体壳宽、壳高和体重的测量 ,比较不同群体的生长情况。同时采用RAPD技术对F1 代不同群体的遗传结构进行比较 ,研究群体内的遗传变异与杂种优势的关系。结果表明 ,杂交后代具有明显的生长优势 ,说明栉孔扇贝种内不同种群之间存在杂种优势。韩国野生种群和中国养殖群体以及发病区存活群体的遗传距离分别为 0 0 3 6 6和 0 0 0 5 7,以上 4个F1 代群体的平均杂合度的理论值分别为 0 2 83、0 2 6 7、0 2 6 8和 0 2 6 6 ;多态位点比例分别为 0 76 5、0 76 0、0 76 0、0 73 5。表明栉孔扇贝不同地理种群之间存在遗传分化 。

Crossbreeding of Chlamys farreri was performed using the parent scallops from the Korea wild population,China cultured stock and the survived individuals in epedimic waters in culture areas of China.Four crosses,Korea wild population×Korea wild population,Korea wild population×China cultured stock,Korea wild population×survived individuals in epedimic waters in culture area of China and China cultured stock×China cultured stock,were constructed. The index of growth performance of their progenies such as the length and width of the shell and the individual weight were measured for heterosis study.Population genetic structure was studied using RAPD analysis to reveal the relationship between the genetic variations and heterosis.The index of growth performance of hybrids between Korea wild population and China cultured stock was better than their parents,which indicated that heterosis existed between different populations of C.farreri.RAPD analysis revealed that the genetic distances between Korea wild population and China cultured stock,and the stock of survived individuals in China epedimic waters were 0.036 6 to 0.050 7,respectively.The mean expected hetrozygosities of the above populations were 0.283,0.267,0.268,and 0.266,respectively,and the proportions of polymorphic loci were 0.765,0.760,0.760 and 0.735,respectively.The results indicated that the genetic differentiation occurred between the different geographic populations of C.farreri.