尼罗罗非鱼8个养殖群体线粒体控制区遗传多样性和遗传关系分析

 利用线粒体DNA控制区部分序列对中国8个尼罗罗非鱼 (Oreochromis niloticus) 养殖群体(埃及、吉拉达、美国、鹭业、吉诺玛、宝路、广东、新吉富)的遗传多样性和相互间遗传关系进行了分析。在所分析的237个样本中, 可归结为15种单倍型, 其中单倍型BL1为宝路(BL)、埃及(EGY)、吉拉达(GLD)、吉诺玛(GNM)和鹭业(LY) 5个群体所共享, 但没有一个单倍型为所有群体共享。8个群体内的核苷酸多态位点数(S)在4~83, 平均核苷酸差异数(K)的范围为0.50~37.26, 单倍型多样性(h)为0.190 8~0.802 3, 核苷酸多样性(π)为0.000 8~0.056 9。AMOVA分析与群体间两两比较的遗传分化指数(F_ST)表明, 这些罗非鱼群体存在显著的遗传分化与差异(P<0.01)。利用Kimura two-parameter模型分析的系统发育关系表明: 宝路、广东和新吉富3个群体亲缘关系较近, 它们聚为一大支; 埃及、美国、吉拉达、鹭业、吉诺玛这5个群体聚为另一大支。单倍型网络(NETWORK)结果显示, 8个群体并没有明显的谱系分化。本研究结果旨为尼罗罗非鱼种质资源的聚合利用奠定基础。

Genetic diversity and relationships of mitochondrial DNA control region from the eight domesticated populations of Nile tilapia

Tilapia is one of the most extensively cultured species in aquaculture with great economic importance, and has been introduced to nearly 100 countries in the world. China is the biggest country in tilapia production, accounting for about 55% of the total production in the world. In which, Nile tilapia () has played an important role in developing tilapia industry. Since 1978, Nile tilapia first introduced to China, it has been multiply introduced from different countries or areas for several times. Consequently a number of domesticated strains or populations have been established and developed with different selective pressures and divergent genetic characteristics in China. This gives us a chance to combine multiple germplasm resources in breeding practices of tilapia. However, the genetic evaluation and investigation of these domesticated populations of Nile tilapia in China have been relatively poorly conducted. In this study, genetic diversity and genetic relationships of the eight domesticated populations of Nile tilapia in China were examined using partial mitochondrial control region (D-loop) sequence, including the Egypt (EGY), Gilada (GLD), American (USA), Luye (LY), Genomar (GNM), Baolu (BL), Guangdong (GD) and New GIFT (NGF) populations. The results showed that only 15 haplotypes were defined in the 237 analyzed individuals, in which, BL1 haplotype was shared by the five populations (BL, EGY, GLD, GNM, LY), but no one shared haplotype was found for all the populations. The Number of variable sites (), haplotype diversity () and 4 to 83, 0.50 to 37.26, 0.190 8 to 0.802 3 and0.000 8 to 0.056 9, respectively. The genetic diversity in the LY was the lowest in the eight populations analyzed. The results of analysis of molecular variance (AMOVA) indicated significant genetic divergence (<0.01) among the populations. The cluster analysis based on Kimura two-parameter model exhibited the two clusters among them, one cluster included the three populations of BL, GD and NGF, and another cluster consisted of the five populations of EGY, LY, GNM, GLD and USA. However, it was not well supported by the haplotype network profile in network. This study provided insight into the genetic basis of Nile tilapia in combining their germplasm in future