基于D-loop序列的吉富罗非鱼遗传变异分析

Genetic Variation of GIFT Strains of Oreochromis Niloticus Based on D-loop Sequence

运用PCR技术扩增吉富罗非鱼选育群体第20和21世代D-loop区799 bp序列并进行群体遗传变异分析.序列组成分析显示两代群体的A和T含量较为接近,A+T含量明显高于G+C含量.两代群体的D-loop序列中度变异,群体间遗传变异较小,遗传分化主要发生在群体内.中性检验(Tajima’s D和Fu and Li’s D)分析结果显示两群体不遵循中性进化模型,以中等频率的等位基因为主.基于D-loop序列进行的遗传多样性分析显示,两代群体的多态性位点、平均核苷酸差异数、单倍型多样性、核苷酸多样性等参数较大,且两代群体属于高单倍型多样性和高核苷酸多样性的遗传多样性模式.本研究为吉富罗非鱼的分子标记选育提供参考依据.

In the current study, D-loop sequences of GIFT strains of Oreochromis niloticus were amplified by PCR to analyze the genetic variation of the 20 th and 21 st generation. Sequence composition analyses showed that the content of A and T are relatively close in these two generations, yet the content of A＋T is significantly higher than that of G＋C. The D-loop sequences of the two generations are moderate variation, with small genetic variations between the two groups and genetic differentiation mainly occurring within groups. Neutral test （Tajima’s D and Fu and Li’s D） showed that two groups do not follow the neutral evolutionary model, with the allele with median frequency as the main genes. Genetic diversity analyses based on D-loop sequences showed that the parameters of genetic diversity—polymorphism sites, average number of nucleotide differences, haplotype diversity and nucleotide diversity—are at high levels. Moreover, the two generations belong to the pattern of high level of haplotype diversity and nucleotide diversity. This study provides a reference for the breeding of GIFT strains of Oreochromis niloticus based on molecular markers.