团头鲂3个选育群体遗传潜力的微卫星分析

Genetic potential analysis of three selective breeding populations of blunt snout bream (Megalobrama amblycephala) using microsatellite markers

  • 摘要: 为从遗传多样性的角度了解团头鲂(Megalobrama amblycephala)3个选育群体的遗传潜力,该研究以团头鲂“浦江1号”选育奠基群体(F0)为对照组,采用14个多态性转录组微卫星标记评估了团头鲂3个选育群体的遗传多样性,分析其遗传潜力。结果显示,3个选育群体平均每个位点的等位基因数(A)为7.928 6~8.785 7,有效等位基因数(AE)为4.409 4~4.878 4,观察杂合度(HO)为0.491 1~0.574 4,期望杂合度(HE)为0.741 3~0.751 8,多态信息含量(PIC)为0.691 2~0.705 2,近交系数(FIS)为0.229~0.352。3个选育群体的遗传多样性水平(AEHE)均高于F0群体,但不存在显著差异(P>0.05)。3个选育群体的有效群体大小(Ne)为11.0~29.3,在近期可能经历过遗传瓶颈。3个选育群体间DADSW遗传距离分别为0.175 4~0.358 8、0.804 7~1.054 4。该结果表明,3个选育群体的遗传多样性较高,遗传潜力较大,但因有效群体数量较少和瓶颈效应的影响,存在杂合度下降和近交衰退的风险,今后需采取科学措施来保护选育群体的遗传潜力。

     

    Abstract: In order to understand the genetic potential of three selective breeding populations of blunt snout bream (Megalobrama amblycephala), the genetic diversity were assessed in four populations three selective breeding populations and one foundation population (F0) of "Pujiang No.1" selected strain of blunt snout bream on 14 polymorphic transcriptomic microsatellite loci. The parameters of genetic variabilities in three selective breeding populations are summarized as follows:the average number of alleles (A) was 7.928 6~8.785 7;the average number of effective alleles (AE) was 4.409 4~4.878 4;the value of average observed heterozygosity (HO) was 0.491 1~0.574 4;the value of average expected heterozygosity (HE) was 0.741 3~0.751 8;the value of average polymorphism information content (PIC) was 0.691 2~0.705 2;the value of average Wright′s inbreeding coefficient (FIS) was 0.229~0.352. The genetic diversity indices of AE and HE in three selective breeding populations were higher than those in foundation population (F0). The LSD-t test shows that no significant difference (P>0.05) existed between foundation population (F0) and three selective breeding populations in terms of AE and HE. Estimation of effective population size (Ne) for three selective breeding populations was 11.0~29.3. Recent genetic population bottleneck was detected in three selective breeding populations. The genetic distance (DA, DSW) among three selective breeding populations were 0.175 4~0.358 8 and 0.804 7~1.054 4, respectively. Relatively high genetic diversity and genetic potential were maintained in three selective breeding populations. Low effective population size and bottleneck effect may lead to loss of heterozygosity and inbreeding depression. Scientific measures should be taken to protect the genetic potential of selective breeding populations in the future.

     

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