A twinovary mutant derived from the doubled haploid (DH) progeny of a cross,02428/Gui 630, was presumably related to the transposition of some transposable elements. Up to date, all reported the active transposable elements in rice (Oryza sativaL.) are copia like retrotransposons. In the present study, the reverse transcriptase domains of copia like retrotransposons were amplified from the total DNA isolted from the mutant plants with the degenerated oligonucleotide primers for the domain. Three cloned insert DNAs, R331, R334 and R338, representing putative different copialike retrotransposons were screened out. Two of them displayed high polymorphism between “Zhaiyeqing 8” and “Jingxi 17”. Nine of the polymorphic bands were mapped on seven rice chromosomes. Sequencing analysis revealed that stop codons frequently occur in the sequence of R338, while both R331 and R334 contain a continuous coding region for 81 putative amino acid residues. No significant variation in hybridization patterns was found between indica and japonica rice or among 26 varieties of indica rice when R33 1 was used as a probe. Nevertheless, when R33 4 was used as a probe, high polymorphisms were detected both between indica and japonica rice and among 26 indica varieties, implying that this element might still be active in rice genomes.
水稻双子房突变体中类copia逆转座子同源序列的研究
王文明1 邢少辰1，2 郑先武1 赵显峰1朱立煌1*
（1。中国科学院遗传研究所植物所植物生物技术重点实验室，北京100101）；2。四川农业大学水稻研究所，成都611130
摘要：以水稻双子房突变体的总DNA为模板 ,用简并引物扩增类copia逆转座子的逆转录酶区域。从PCR产物中分离到代表 3个不同的类copia逆转座子的片段 ,其中两个在水稻 (OryzasativaL .)品种“窄叶青 8号”和“京系 17”间产生的多态性杂交带分别定位于水稻 7条染色体的 9个位点。R33 8含大量的终止码 ,R33 1及R33 4为连续的编码区 ,推测的氨基酸序列含 81个氨基酸残基。R33 1的拷贝数变化不明显 ,R33 4在籼粳亚种间及 2 6个籼稻品种间具有广泛的多态性 ,暗示了在籼粳分化后晚近的转座事件。这一结果对进一步分离水稻中有活性的转座因子及建立克隆和探测水稻基因功能的转座子诱变系统具有促进作用
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