| 红壳色文蛤选育群体遗传多样性的微卫星分析 |
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| 引用本文： | 田镇,陈爱华,曹奕,吴杨平,张雨,陈素华,张志东,李秋洁.红壳色文蛤选育群体遗传多样性的微卫星分析[J].南方农业学报,2021,52(9):2582-2589. |
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| 作者姓名： | 田镇 陈爱华 曹奕 吴杨平 张雨 陈素华 张志东 李秋洁 |
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| 作者单位： | 1 江苏省海洋水产研究所, 江苏南通 226007;2 上海海洋大学/水产科学国家级实验教学示范中心, 上海 201306 |
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| 基金项目： | 江苏省渔业科技类重大项目（D2018-1）；江苏省自然科学基金面上项目（BK20181201）；江苏省科技厅苏北专项（SZYC2018064）；江苏省水产良种保种及亲本更新项目（2020-SJ-006） |
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| 摘 要： | 【目的】了解群体选育过程中红壳色文蛤（Meretrix meretrix）选育群体的遗传多样性变化及世代遗传分化情况，为文蛤育种计划的可持续性提供理论依据。【方法】以江苏黄文蛤原种（SY）、江苏红文蛤原种（SR）及5个红壳色文蛤选育群体（SRF1~SR5F5）为研究对象，利用15对微卫星引物对各文蛤群体基因组DNA进行PCR扩增，然后通过Gel-Pro32 4.0、PopGen 32和MEGA 6.0等在线软件分析7个文蛤群体的遗传多样性。【结果】从7个文蛤群体中共检测出766个等位基因，每个微卫星位点在每个群体中检测出3~18个等位基因，且等位基因数（Na）随选育世代增加呈下降趋势。15个微卫星位点的平均多态信息含量（PIC）在0.575~0.630，均属于高度多态性位点。7个文蛤群体的平均观测杂合度（Ho）为0.442~0.502，平均期望杂合度（He）为0.629~0.680，群体中63.81%的微卫星位点偏离Hardy-Weinberg平衡，表明各微卫星位点存在一定程度的杂合子缺失；群体内近交系数（Fis）范围为-0.0157~0.7409，平均为0.2777，表明文蛤群体内存在一定程度的近交水平；群体间遗传分化系数（Fst）平均为0.0455，即文蛤群体变异中仅有4.55%是由不同群体间的基因差异所产生，而95.45%的变异来源于群体内部；各群体的基因流（Nm）为0.9002~18.9478，平均为8.8065，说明7个文蛤群体间的遗传分化较低。UPMGA聚类分析发现7个文蛤群体聚类呈两大支，江苏红文蛤原种及其选育群体聚为一支，而江苏黄文蛤原种（SY）独自聚为一支。【结论】经过5代人工选育的红壳色文蛤选育群体虽然较基础群体其遗传多样性指数略有下降，但并未导致各选育群体的遗传结构发生改变，仍具有较高的遗传多样性。在连续的选择育种计划中，应增加亲本养殖环境多样化，避免因人工繁育的亲本和养殖群体规模较小引起遗传漂移或近交衰退而致使某些等位基因缺失，导致后代的遗传结构发生改变。
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| 关 键 词： | 文蛤 红壳色 群体选育 微卫星 遗传多样性 遗传漂移 |
| 收稿时间： | 2020-10-10 |
Microsatellite analysis on genetic diversity of breeding populations of red shell color Meretrix meretrix |
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| TIAN Zhen,CHEN Ai-hua,CAO Yi,WU Yang-ping,ZHANG Yu,CHEN Su-hua,ZHANG Zhi-dong,LI Qiu-jie.Microsatellite analysis on genetic diversity of breeding populations of red shell color Meretrix meretrix[J].Journal of Southern Agriculture,2021,52(9):2582-2589. |
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| Authors: | TIAN Zhen CHEN Ai-hua CAO Yi WU Yang-ping ZHANG Yu CHEN Su-hua ZHANG Zhi-dong LI Qiu-jie |
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| Affiliation: | 1 Jiangsu Institute of Marine Fisheries, Nantong, Jiangsu 226007, China;2 Shanghai Ocean University/National Experimental Teaching Demonstration Center of Aquatic Science, Shanghai 201306, China |
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| Abstract: | 【Objective】 In order to understand the genetic diversity and generational genetic differentiation of breeding populations of red shell color Meretrix meretrix during population selection,and to provide theoretical basis for long-term sustainability of breeding programs.【Method】 In this study,fifteen pairs of microsatellite markers were used to analyze seven populations of M. meretrix,including Jiangsu wild population with yellow shell(SY),wild population with red shell(SR)and five generations selected consecutively though red shell and shell length(SRF1-SR5F5). Fifteen pairs of microsatellite primers were used for PCR amplification of genomic DNA of sevenpopulations. The genetic diversity of seven populations was analyzed by online softwares such as Gel-Pro32 4.0,PopGen 32 and MEGA 6.0.【Result】 The results showed that a total of 766 alleles were detected in seven populations, and 3 to 18 alleles were detected at each microsatellite locus in each population. The number of alleles(Na)decreased with the increase of breeding generations. The mean polymorphic information content(PIC)of the 15 microsatellite loci ranged from 0.575 to 0.630,so they were highly polymorphic loci. The average observed heterozygosity(Ho)and expected heterozygosity(He)were 0.442-0.502 and 0.629-0.680,respectively. 63.81% of microsatellite loci deviated from Hardy-Weinberg equilibrium,indicating a certain degree of heterozygous deletion at each microsatellite locus. The number of inbreeding lines(Fis)ranged from -0.0157 to 0.7409,with an average of 0.2777,indicating that there was a certain level of inbreeding in the population. The average coefficient of genetic differentiation(Fst)between populations was 0.0455,that was,4.55% of the population variation was caused by gene differences between different populations,and 95.45% of the population variation was from within populations. The gene flow(Nm)of each population ranged from 0.9002 to 18.9478,with an average of 8.8065,indicating low genetic differentiation among the seven populations. UPMGA cluster analysis showed that the seven clam populations clustered into two branches,the SR and its breeding population clustered into one branch,and SY clustered into one branch.【Conclusion】 After five generations of artificial selective breeding,the genetic diversity index of the selected population decreased slightly compared with SR and SY,but the genetic structure of the selected population did not change andthey still had a high genetic diversity. In the continuous selective breeding program,the breeding environment of parents should be diversified to avoid the genetic drift or inbreeding decline caused by the small size of artificially bred parents and breeding population,which leads to the deletion of some alleles in breeding population and the change of genetic structure of offspring. |
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