中文摘要：

对坛紫菜（Porphyra haitanensis）野生（GL）和栽培（PXV）品系的5.8SrDNA-ITS区进行了PCR扩增和序列分析,扩增的GL和PXV的DNA片段长度分别为1213bp和1221bp,包含完整的ITS1-5.8S-ITS2区。然后对紫菜7个种9个品系（其中6种7个品系从GenBank数据库中获得）的rDNA相应序列进行了排序和系统进化分析,结果表明：9个紫菜品系rDNA中5.8S区的长度和序列非常保守,而ITS区的长度和序列则变异较大;根据它们的序列差异,计算出这9个紫菜品系的遗传距离在0.010-0.551之间,遗传相似性在44.9%-99%之间;并且采用邻接法构建了这9个紫菜品系的系统发育树,发现可以明显分为4个进化枝,由此讨论了分子分类方法同传统分类方法的分歧。实验结果表明,5.8SrDNA-ITS区序列可以成为紫菜种质鉴定和系统进化研究的强有力工具。

英文摘要：

The intemal transcribed spacer （ITS） regions of nuclear ribosomal DNA （including 5.8S rDNA） of wild-type （GL） and cultivated （PXV） P. haitanens/s were amplified and their sequence was analyzed by NCBI blast： the length of GL and PXV rDNA- ITS amplified fragments was 1213 and 1221 bp respectively, and the fragments contained integrity ITS1-5.8S-ITS2 regions. Then the sequences of 9 Porphyra lines （among them 7 other Porphyra rDNA sequences were downloaded from the GenBank） were aligned by comparing the rDNA corresponding regions, and the results indicated that the length and sequences of 5.8S rDNA regions were very conservative, but the ITS regions were diversity. Based on their sequences diversity, the genetic distances and genetic similarity among the 9 Porphyra lines were 0.010 - 0.551 and 44.9% - 99% respectively. At last, the phylogenetic tree of the 9 Porphyra lines was constructed by NJ methods and it showed that the 9 Porphyra lines were divided into 4 monophyletic clades. All these results suggest that the sequence analysis of 5.8S rDNA-ITS regions can be a powerful tool in the phylogenetic analysis and variety identification of Porphyra.