埃及品系尼罗罗非鱼不同选育世代 mtDNA D-loop 区遗传多样性分析

摘要

为评价现有选育方式下的遗传结构现状及选育潜力，采用 mtDNA D-loop 序列差异分析技术，对埃及品系尼罗罗非鱼（Oreochromis niloticus）的3个选育世代群体共80尾鱼开展世代间遗传结构变异分析。结果显示：1）3个世代群体中个体序列长度为552~555 bp，包括52个变异位点、12个单倍型，平均单倍型多样度（ H）为0.569；2）3个世代群体的核苷酸多态性（ Pi ）分别为0.0219、0.0403和0.0397，各世代具备较高的多态性；3）3个世代中，F1具有5个单倍型，F2和 F3均具有7个单倍型，F1、F2和 F3共享2个单倍型，F1与 F2共享1个单倍型，3个选育世代群体的单倍型在 NJ 系统树上相互交叉，无独立的进化枝。表明在目前选育方式下埃及品系尼罗罗非鱼世代间遗传信息较为稳定，选育并没有对罗非鱼选育群体的遗传结构造成大影响。%To evaluate the effect of the present breeding ways on genetic structure and breeding potential of Egyptian strain of Oreochro-mis niloticus,we analyzed the variation of mitochondrial DNA D-loop region in their three generations(80 individuals). The results show that:1)The length of the region sequences was 552 ~ 555 bp;52 variable sites and 12 haplotypes were detected. The average haplotype diversity was 0. 569. 2)The nucleotide polymorphisms(Pi )of three generations were 0. 021 9,0. 040 3 and 0. 039 7,re-spectively,each generation showing high polymorphism in the mitochondrial genetic diversity. 3)F1 generation contained five haplo-types;F2 generation contained seven haplotypes;F3 generation contained seven haplotypes. The three generations shared two haplo-tupes,and F1 and F2 generations shared a haplotype. The haplotypes of three generations crossed each other in the NJ tree and no u-nique clade of haplotype existed in each generation. It is concluded that there was no significant variation in genetic structure at the control region sequence in the three generations. The genetic information among three generations of O. niloticus was stable by the pres-ent breeding ways.