我国近岸多室草苔虫(Bugula neritina)的群体遗传分化研究

Population genetic variation study of Bugula neritina in coastal waters of China

基于线粒体控制区序列和SLAF-seq,对重要药源生物多室草苔虫的群体遗传分化水平开展了研究。控制区序列中检测到8个单倍型,单倍型多样性(h)和核苷酸多样性(π)分别为0.130 7和0.000 7,单倍型网络图和NJ系统进化树的结构都较简单,无明显拓扑结构。中性检验和核苷酸不配对分析结果均表明多室草苔虫未经历过大规模群体扩张。Fst和AMOVA分析显示遗传变异主要来自于群体内。SLAF建库共开发得到214 409个SLAF标签,其中多态性SLAF标签23 437个,共开发出99 432个SNP位点。群体间的遗传距离较小,且低于群体内的遗传距离。基于SNP所做的系统发育树和群体遗传结构分析表明,各群体之间没有显著的遗传结构。综上所述,我国沿海多室草苔虫的遗传多样性水平较低,不同地理群体之间不存在显著的遗传结构。多室草苔虫较强的扩散能力是造成上述结果的主要原因。另外,本研究还验证和讨论了SLAF-seq应用在海洋生物群体遗传分化研究中的可行性和优势。

We studied the genetic diversity and population genetic variation of Bugula neritina,an important pharmaceutical organism,sampled from 4 distinct localities along China coastline by mitochondrial control region amplification and SLAF-seq.8 haplotypes were detected in control region,haplotype diversity（h）and nucleotide diversity（π）were 0.130 7 and 0.000 7,respectively.No significant topological structure was found in haplotype network and NJ phylogenetic tree.Neutrality tests and mismatch distribution both suggested that B.neritinadid not experience a range expansion.Fstand AMOVA analysis indicated that genetic variation mainly occurred within populations.SLAF library construction generated 214 409 SLAFs,among which 23 437 were polymorphic,99 432 SNP loci were developed.Genetic distances among populations were short and even shorter than those within populations.Phylogenetic tree and population genetic analysis based on SNP data revealed that no significant genetic structure were observed among populations.In conclusion,genetic diversity of B.neritinain coastal waters of China were low,and no significant genetic structure existed among geographically distinct populations.We assumed this was mainly attributed to bryozoan＇s capability to disperse.In addition,our study validated the application and advantages of SLAF-seq in population genetic variation study of marine organisms.