罗氏沼虾不同育种群体遗传多样性研究

GENETIC DIVERSITY OF THE BREEDING POPULATIONS OF GIANT FRESHWATER PRAWN MACROBRACHIUM ROSENBERGII

  • 摘要: 为深入了解罗氏沼虾(Macrobrachium rosenbergii)不同种质资源的遗传背景, 研究采用微卫星标记和线粒体基因相结合, 对罗氏沼虾4个育种群体, 即选育3代的数丰核心群体(SF)、引进的正大群体(ZD)、正大和数丰杂交的群体(ZDS)、正大子代和数丰杂交的群体(ZD2S)的遗传多样性进行了研究。150个个体的微卫星分析结果显示, 7个微卫星位点均表现出高度多态性(PIC>0.5), 4个群体平均的等位基因数(Na)、期望杂合度(He)和多态信息含量(PIC)分别为19.43、0.8980和0.8867。SF群体的平均He (0.874)和PIC (0.854)最高, ZD2S的He (0.863)和PIC (0.834)其次, ZDS群体的He (0.798)和PIC (0.761)最低。4个群体间的遗传分化指数(FST)为0.04166—0.10438, 处于中低水平的遗传分化, 其中, ZD和ZDS的遗传分化最大, FST为0.10438。线粒体COⅠ和12S rRNA基因组合序列分析结果显示, 149个个体共识别27个单倍型, 平均单倍型多样性(Hd)和核苷酸多样性(π)分别为0.846和0.00313。在4个群体中, ZD2S群体的Hd值最高, 其次为SF群体, ZDS的最低; 对于π值, SF群体的最高, 其次为ZD2S群体, ZD群体的则最低, 该结果与微卫星的结果基本一致。但基于线粒体基因的群体间遗传分化较小, FST值为–0.02226—0.07310, 小于微卫星估计的结果。微卫星和线粒体基因一致表明, SF和ZD2S两个群体均保持着较高的遗传多样性, 具有进一步选育的潜力。

     

    Abstract: To learn the genetic background of the giant freshwater prawn (Macrobrachium rosenbergii), four different breeding populations, including Shufeng nucleus breeding population selected for three generations (SF), introduced Zhengda population (ZD), hybrid population between the introduced Zhengda population and Shufeng population (ZDS), and hybrid population between the progeny of the introduced Zhengda population and Shufeng population (ZD2S), were investigated by using both microsatellite loci and mitochondrial COⅠand 12S rRNA genes as molecular markers. The microsatellite data of 150 individuals revealed that all the seven loci had high diversity with PIC>0.5. The average number of alleles (Na), expected heterozygosity (He) and polymorphism information content (PIC) were 19.43, 0.8980 and 0.8867, respectively. Among seven loci of four populations, the average He (0.874) and PIC (0.854) of the SF were the highest, followed by He (0.863) and PIC (0.834) of the ZD2S, and the lowest He (0.798) and PIC (0.761) of the ZDS. The pairwised genetic differentiation indices (FST) among the four populations was 0.04166—0.10438, suggesting low to moderate genetic differentiations. The FST between ZD and ZDS was the highest with a value of 0.10438. Based on the concatenated mitochondrial COⅠ and 12S rRNA gene sequences, 149 individuals contained 27 haplotypes, with the average haplotype diversity (Hd) and nucleotide diversity (π) of 0.846 and 0.00313, respectively. Among four populations, the Hd of the ZD2S was the highest, followed by the SF, and ZDS was the lowest. For the π values, the SF was the highest, followed by ZD2S, and ZD was the lowest, which was generally consistent with the genetic diversity results analyzed based on microsatellite data. However, the genetic differentiation among four populations based on mitochondrial genes was low with FST values of –0.02226—0.07310, which is much lower than those based on microsatellite. These results indicated that both SF and ZD2S maintain high genetic diversity and have the potential for further selective breeding of Macrobrachium rosenbergii.

     

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