野生与养殖厚壳贻贝体框特征和线粒体16S rRNA基因的比较分析

Comparative analysis of shell frame characteristics and mitochondrial 16S rRNA gene between wild and cultured mussels (Mytilus coruscus)

  • 摘要: 了解厚壳贻贝 (Mytilus coruscus) 的生活环境对其生长的影响,对贻贝养殖业的高质量发展极为重要。以枸杞岛潮间带野生和浮筏养殖厚壳贻贝为研究对象,构建以壳长为基准的13个体框特征指标 (包括壳宽、壳高等),比较两种厚壳贻贝的主要形态特征,并结合线粒体16S rRNA 基因的序列信息,分析其遗传关系与形态特征的关联性。结果表明,野生和养殖贻贝有10个体框特征指标存在显著性差异 (P<0.05),野生的贝壳整体更宽厚、质量更大。应用逐步判别法筛选出的壳宽 (L1)、壳高 (L2)、壳顶至铰合部上端的距离 (L10)、壳顶至足丝孔的距离 (L12) 4个变量对野生和养殖厚壳贻贝的综合判别准确率达到94.9%。16S rRNA基因测序结果显示,野生厚壳贻贝的核苷酸多样性 (π) 为0.089,单倍型多样性 (Hd) 为0.894;养殖厚壳贻贝的π为0.087,Hd为0.682。野生与养殖厚壳贻贝的遗传多样性水平均较高,但系统发育树和单倍型网络图证明二者不存在显著的遗传分化,推测其形态差异可能主要受栖息环境 (波浪暴露强度、营养条件) 影响。

     

    Abstract: Understanding the impact of the environment of Mytilus unguiculatus on its growth is extremely important for promoting high-quality development of mussel breeding industry. Taking the wild (From Gouqi intertidal area) and cultured (From mussel culture rafts) M. coruscus as research objects, we constructed 13 shell frame characteristics indexes based on shell length, including shell width and shell height to compare their main morphological differences, and sequenced their 16S rRNA gene to analyze the genetic and morphological associations between them. The results show that there were significant differences in ten shell frame characteristics between wild and cultured mussels (P<0.05), and the shells of wild mussels were generally wider, thicker and heavier. Four variables were selected by stepwise discrimination method: L1 (Shell width), L2 (Shell height), L10 (Distance from the top of shell to the upper end of hinge), L12 (Distance from the top of shell to the byssus orifice). The comprehensive discrimination accuracy of wild and cultured mussels was 94.9%. The 16S rRNA gene sequencing shows that the wild mussels nucleotide diversity (π) was 0.089, and haplotype diversity (Hd) was 0.894; cultured mussels' π was 0.087 and Hd was 0.682. The genetic diversity level of wild and cultured mussles were relatively high, but the phylogenetic tree and haplotype network prove that there was no significant genetic differentiation between them. It is speculated that their morphological differences might be mainly influenced by their habitat environments (Wave exposure, growth density, etc.).

     

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