中国沿海日本囊对虾线粒体16S rRNA基因序列变异及遗传分化

对中国东南沿海4个日本囊对虾地理群体16S rRNA基因片段进行了序列测定和分析.在获得的467bp 序列中,共检测到45个变异位点,多态位点比例为9.64%.具有10种单倍型,三亚群体单倍型多样性最高(0.900±0.161).各群体的核苷酸多样性(π)为0.0007～0.0082,其中三亚群体核苷酸多样性最为丰富,远高于湛江、北海和海口群体.群体间遗传分化指数(F_(st))为0.000～0.945.结合已报道的16S rRNA基因序列,构建了NJ分子系统树,中国海域日本囊对虾可分为3支.香港至台湾沿岸所有单倍型聚集为一分支,湛江、海口和北海群体内的所有单倍型聚集成另一分支,两分支分别属于已报道的变种Ⅰ和变种Ⅱ,但三亚群体内的4个单倍型单独聚集成一分支,与前两分支的核苷酸序列差异大(7.95%～8.35%),遗传分化明显,可能为一亲缘关系很远的新种(或变种).研究结果可为日本囊对虾的资源管理和遗传选育提供参考.

Sequence variability of mitochondrial 16S rRNA gene and genetic divergence of Marsupenaeus japonicus in the costal waters of China

Genetic variation and differentiation of four Marsupenaeus japonicus stocks collected from the coastal waters of southeast China were investigated based on 467 bp nucleotide sequences of mitochondrial 16S rRNA. Among 467 bp sequences, 45 variable sites (9.64%)were detected.. Comparisons of these 25 sequences revealed 10 haplotypes. The haplotype diversity (h) of Sanya stock was the highest(0.900±0.161). Also the nucleotide diversity (π) of SY stock was far higher than that of other three stocks and was ranged from 0.0007 (BH) to 0.0082 (SY). The F_(st) values calculated by the analysis of molecular variance (AMOVA ) ranged from 0.00 to 0.945. Combined with other reported 16S rRNA gene sequences of M.japonicus, the neighbor-joining (NJ) tree of haplotypes suggested that there are three existed clades. One clade included ZJ, BH and HK haplotypes, all haplotypes from Hongkong to Taiwan coastal waters formed another clade, these two clades clustered first and belong to the reported varieties Ⅰand varietiesⅡ, respectively. Then these two clades clustered with the third clade (included four SY haplotypes). The nucleotides variation between Sanya clade and other two clades was very high (7.95%-8.35%). One new species (or varieties) may exist in Sanya waters. Further study should be conducted to get more evidences to verify this result. Results can offer genetic basis for resource management and further breeding program.