Molecular evolutionary studies on the origin of eukaryotes-Analyzes of informational macromolecules.

为了探讨真核生物的进化起源，用常规方法检测了包括家蚕微孢子虫在内的一些微孢子虫的核糖体RNA基因序列和延伸因子，这些微孢子虫被认为是真核生物早期分化的。M12和Pleistophora sp.从它们的孢子中提取总基因组DNA，用合适的引物对目的基因进行PCR扩增。从上述4个样品中获得了小亚基核糖体RNA(SSU RRNA)基因的全序列。与普通原核生物相比，SSU rRNA的长度较短，由该序列构建的二级结构模型缺少真核SSU rRNA常见的几个茎。这一事实可能表明微孢子虫SSU rRNA仍处于原始进化阶段，由于缺乏合适的引物来扩增该基因，对延长因子进行测序的尝试失败了。

In order to investigate the evolutionary origin of eukaryotes, the sequences of ribosomal RNA genes and elongation factors of some microsporidia including Nosema bombycis which is believed to diverge at early stage of eukaryotes are examined by conventional methods.The originisms used were two strains of N.bombycis, Vairimorpha sp. M12 and Pleistophora sp.. The target genes were PCR-amplified by using appropriate primers from the total genomic DNA which had been extracted from their spores. The complete sequences of the small subunit ribosomal RNA (SSU rRNA) genes were obtained from the above four samples. The lengths of the SSU rRNAs were shorter than those of ordinary prokaryotes, and the secondary structure models constructed from the sequence lacked several stems which are common for the eukaryotic SSU rRNAs. This fact may indicate that the microsporidian SSU rRNA stayd in the primitive evolutional stage.Attempt to sequence the elongation factors was failed because of the lack of information for the appropriate primers to amplify the gene.