罗氏沼虾同工酶表达组织差异性及遗传多样性分析

【目的】从生化遗传角度分析罗氏沼虾群体的同工酶基因座及其酶谱表型，明确不同群体的遗传多样性，为其种质资源鉴定及遗传育种研究等提供基础数据。【方法】采用聚丙烯酰胺凝胶电泳（PAGE）对罗氏沼虾肌肉、复眼、鳃、心脏和肝胰腺等5种组织中的苹果酸脱氢酶（MDH）、超氧化物歧化酶（SOD）、山梨醇脱氢酶（SDH）、苹果酸酶（ME）、磷酸葡萄糖变位酶（PGM）、乙醇脱氢酶（ADH）、葡萄糖-6-磷酸脱氢酶（G6PDH）、乳酸脱氢酶（LDH）、谷氨酸脱氢酶（GDH）、天冬氨酸脱氢酶（AAT）和酯酶（EST）等11种同工酶进行电泳分析，并选取肌肉同工酶对申漕群体、野生群体、抗病群体、生长群体和浙江群体（2017年引进种虾）等5个罗氏沼虾群体进行遗传学研究。【结果】同种同工酶在罗氏沼虾不同组织间所表现出的酶谱总数和酶带颜色（酶活性）存在明显差异，即罗氏沼虾同工酶具有明显的组织差异性；11种同工酶在罗氏沼虾5种组织中存在26个基因座。其中，EST在肌肉中未表达，但在肝胰腺中表达较多；ME在肌肉、复眼、鳃、心脏和肝胰腺等5种组织中均有表达；SOD-2只在肝胰腺中表达；PGM在肝胰腺和心脏中表达较多。罗氏沼虾肌肉中的7种同工酶存在11个基因座，有3个基因座（SDH-1、PGM-3和LDH-1）呈多态性，多态位点比例为27.27%。5个罗氏沼虾群体的平均预期杂合度在0.1006~0.1416，平均观测杂合度在0.1143~0.1762，Hardy-Weinberg遗传偏离指数（0.1362~0.2444）均为正值，即偏离Hardy-Weinberg平衡。【结论】罗氏沼虾同工酶具有明显的组织差异性，表现为不同组织间的酶谱总数和酶带颜色（酶活性）存在明显差异，因此同工酶可作为研究罗氏沼虾遗传多样性的一种生化遗传标志。5个罗氏沼虾群体均处于杂合子过剩状态，其遗传变异水平较高。

Isozyme expression tissue difference and genetic diversity of Macrobrachium rosenbergii

【Objective】The isozyme locus and zymogram phenotypes of Macrobrachium rosenbergii population were analyzed from the perspective of biochemical genetics, so as to clarify the genetic diversity of different populations, and provide basic data for the identification of germplasm resources and genetic breeding research.【Method】In this experiment, malic acid dehydrogenase(MDH), superoxide dismutase(SOD), sorbitol dehydrogenase(SDH), malic enzyme (ME), phosphopanase(PGM), alcohol dehydrogenase(ADH), glucose-6-phosphate dehydrogenase(G6PDH), lactate dehydrogenase(LDH), glutamate dehydrogenase(GDH), aspartate dehydrogenase(AAT) and esterase(EST) in muscles, eyes, gills, heart and hepatopancreas of M. rosenbergii were studied by polyacrylamide gel electrophoresis(PAGE). And muscle isozymes were selected to study the genetics of five populations of M. rosenbergii, including Shencao population, wild population, disease resistant population, growth population and Zhejiang population(introduced species of shrimp in 2017).【Result】There were obvious differences in the total number of zymograms and the color of enzyme bands (enzyme activity) of the same isozymes in different tissues of M. rosenbergii, that was, the isozymes of M. rosenbergii had obvious tissue difference. There were 26 loci of 11 isozymes in 5 tissues of M. rosenbergii. Among them, EST was not expressed in muscle, but more in hepatopancreas;ME was expressed in muscle, compound eye, gill, heart and hepatopancreas;SOD-2 was only expressed in hepatopancreas;PGM was expressed more in hepatopancreas and heart. There were 11 loci in the 7 isozymes in the muscle of M. rosenbergii. Three loci(SDH-1, PGM-3 and IDH-1) were polymorphic, and the proportion of polymorphic loci was 27.27%. The average expected heterozygosity of the five M. rosenbergii populations was 0.1006-0.1416, the average observed heterozygosity was 0.1143-0.1762, and the Hardy-Weinberg genetic deviation index(0.1362-0.2444) was positive, that was, it deviated from the Hardy-Weinberg equilibrium.【Conclusion】The isozymes of M. rosenbergii have obvious tissue difference, which shows that there are obvious differences in the total number of zymograms and the color(enzyme activity) of enzyme bands between different tissues. Therefore, the isozymes can be used as a biochemical genetic marker to study the genetic diversity of M. rosenbergii. The five populations are all in the state of heterozygote excess, and their genetic variation levels are high.