Abstract: The sequence of rDNA Intergenic Spacer Region (ISR) was determined for the species Oscillatoria sp.(Cyanobacteria). The spacer sequences was 427bp in lengh exclusive of 16S and 23S rDNA coding regions, containing a Ile tRNA gene. Based on the analyses of the obtained sequences and the sequences from other three representative species of Oscillatoriaceae, and two species of Microcystis , the evolutionary affiliation among the genera of Oscillatoriaceae was discussed. In addition, the results showed that rDNA Intergenic Spacer Region can be served as a criteria for the identification or the classification of Cyanobacteria within the genus or intraspecies, which may be a useful genetic marker at the species or popu-lation level and may be one of the most suitable regions in the rRNA gene cistron for preparing DNA probes specific to Cyanobacteria species because of the high divergence of this region.

Key words: Oscillatoriaceae

摘要： 采用末端终止法对蓝藻类颤藻科Oscillatoria sp. rDNA 16s－23S基因间隔区进行了序列测定，获得了Oscillatoria sp. rDNA基因间隔区427个核苷酸，其中包含1个异亮氨酸tRNA基因(tRNA11e)。并通过计算机联网从国际分子生物学数据弹库中获取颤藻科其它种的rDNA基因间隔区序列，通过比较分析，从分子水平对颤藻科Oscillatoriaceae属间的某些分类学问题进行了讨论，并根据序列中核苷酸差异值探讨了颤藻科属间界定的分子标准。提出了rDNA基因间隔区是良好的分子标记，可用于“赤潮”或“水华”蓝藻专一性核酸分子探针的研制.

关键词: 颤藻科, rDNA间隔区, 序列分析, 分类学意义