| 摘要: |
| 本研究拟利用微卫星标记分析细鳞鲑（Brachymystax lenok）连续3代选育群体的遗传结构及差异。通过筛选出的22对细鳞鲑微卫星引物，利用PCR进行扩增后进行毛细管凝胶电泳，利用GeneMapper V4.1软件进行图像收集和数据分析。在3代共96个样本中共检测到181个等位基因，各标记检测的等位基因数为2—26个，平均为8.227个；3代平均等位基因数（Na）为6.500—6.773，平均有效等位基因数（Ne）为3.356—3.649，3代间Na和Ne差异均不显著；3代平均观测杂合度（Ho）为0.462—0.530，平均多态信息含量（PIC）为0.459—0.525，平均期望杂合度（He）为0.494—0.566；F2和F3的Ho、He、PIC 3项遗传多样性参数均显著低于F1（P<0.05）；Hard-Weinberg平衡检验结果表明细鳞鲑3代选育群体整体保持了遗传平衡状态，但经Bonferroni校正后，尚有2个标记在F1和F3极限著偏离遗传平衡（P<0.0005），3个标记在F2极限著偏离遗传平衡（P<0.0005）。细鳞鲑在选育过程中通过群体选育等方法注重了对稀有等位基因的保护，在细鳞鲑多代选育过程中保持了较高的多态性水平，但在选育过程中某些等位基因出现了富集现象，3代间的遗传分化也较小，仅1.49%的遗传变异来自群体间，表明细鳞鲑群体尚具有持续选育的潜力。 |
| 关键词: 细鳞鲑 微卫星标记 遗传结构 |
| DOI：10.11693/hyhz20180100022 |
| 分类号:Q789 |
| 基金项目:中央级公益性科研院所基本科研业务费专项，HSY201601号；现代农业产业技术体系专项资金资助，CARS-46号；中国水产科学研究院基本科研业务费，2018HY-ZD0302号；国家水产种质资源平台，2018DKA30470号。 |
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| GENETIC STRUCTURE OF THREE CONSECUTIVE BREEDING GENERATIONS OF BRACHYMYSTAX LENOK REVEALED BY MICROSATELLITE MARKERS |
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HUANG Tian-Qing, XU Ge-Feng, GU Wei, WANG Bing-Qian, ZHANG Yu-Yong, ZHENG Xian-Hu, YAO Zuo-Chun, ZHAO Cheng, LU Cui-Yun
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Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, China
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| Abstract: |
| Brachymystax lenok is a commercially important cold-water fish widely distributed throughout the eastern Siberia including portions of Kazakhstan, Mongolia, China, and Korea. Genetic structure and genetic variation in 96 individuals from three generations of the fish were studied to optimize selective breeding of the fish. Samples of the fin clip were randomly collected from F1, F2, and F3 populations. Total DNA was extracted into the concentration of to 50ng/µL. Samples were amplified by 22 polymorphic microsatellite markers from rainbow trout Oncorhynchus mykiss labeled with FAM (blue) and HEX (green) and analyzed by capillary electrophoresis. A total of 181 alleles were detected in the fragment size of 118-355bp among the 96 individuals. The number of alleles varied from two to 26 per locus in the average of 8.227. The average number of alleles (Na) of F1, F2, and F3 was 6.500, 6.773, and 6.773, respectively. The average number of effect alleles (Ne) of F1, F2, and F3 was 3.649, 3.356, and 3.624, respectively. The Na and Ne value of the 22 markers showed no significant difference among generations. The average observed heterozygosity (Ho) and expected heterozygosity (He) were from 0.462 to 0.5303 and 0.494 to 0.566 among generations, respectively. The average polymorphism information content (PIC) ranged from 0.459 to 0.525. The Ho,He, and PIC of F2 and F3 were significantly lower than that of F1 (P<0.05). The three populations accorded with Hard-Weinberg equilibrium checked by χ2 test. Highly significant deviations from Hardy-Weinberg equilibrium were observed in five markers involving the F1 (OMM1762 and OMM3048), F2 (OMM1145, OMM1329, and OMM3048), and F3 (OMM3048 and OMM5192) after Bonferroni correction (P<0.0005). These deviations were due to heterozygote deficits except of OMM1329 in F2 population. The genetic differentiation is very weak (Fst=0.0149<0.05) with only 1.49% genetic variation between generations. The lenok kept more rare alleles in the process of breeding by population selection, the three populations of lenok were at moderate and high level genetic diversity, and several allele enriching in the selection process. Therefore, the genetic differentiation was very weak, suggesting that the species remained suitable for further selective breeding, which may provide a reference to the germplasm resource protection and continuous selection breeding. |
| Key words: Brachymystax lenok microsatellite genetic structure |
