摘要
In the present study, RAPD technique was used to analyze the geneticrelationship between two cultured populations in china, oreochromis aureus and a niloticus,and the application of this technique in species identification was also investigated. Resultsrevealed that no DNA polymorphism was detected within the population of O.aureus andpolymorphism in varying degrees was observed among individuals. Similarity index andgenetic distance calculated have no remakable difference with data reported by others. RAPDanalysis using mixed samples was also tested in this experiment. In addition, someelectrophoregrams of amplification products also suggested the occurrence of geneticintrogression between the two cultured tilapia populations. Conclusively, RAPD technique isa rapid and efficient method for studying genetic polymorphism within and between differentpopulations, and RAPD markers can be used to identify different fish populations.
以随机扩增多态ＤＮＡ技术（ＲＡＰＤ）分析了奥利亚罗非鱼和尼罗罗非鱼两个养殖群体的群体内及群体间遗传关系，并探讨了该技术在种群鉴定中的应用。ＲＡＰＤ引物筛选结果表明，所测试的２０个随机引物中（Ｔａｂｌｅ １），除一个引物未扩增出任何片段外，其余１９个引物均扩增出１～１１个大小不等的片段，长度大部分在５００～３０００ｂｐ之间，共扩增出２２０个片段，平均每个引物产生５．５个片段。两群体间共有片段７０条，大部分引物的扩增产物具有种间多态性，种群间相似系数为０．７２７。以筛选的引物对两种群不同个体（Ｆｉｇ．１，Ｔａｂｌｅ２）及种群混合样品（Ｆｉｇ．２，Ｔａｂｌｅ３）进行ＲＡＰＤ分析。结果表明，不同引物在扩增图谱上表现很大差异。奥利亚罗非鱼不同个体间表现为一致的扩增图谱，种内相似系数达１０００，显示了其种群内遗传变异的缺乏；尼罗罗非鱼种内相似系数为０．８２７，个体间存在不同程度的多态性；两个种群间的相似系数分别为０．７６７和０．７４２，表明种间有较高的同源性，遗传距离为０．２３５，略低于国外的报道、此外，两个养殖群体间的扩增图谱比较也暗示了遗传渐渗现象的存在。实验表明，ＲＡＰＤ标记可以作为一种可靠的遗传标记。
