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The dynamic aspect of genome structures in plants

植物基因组结构的动态方面

基本信息

批准号：
04304012
负责人：
HIRAI Atsushi
金额：
$ 10.24万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

项目摘要

Dynamic aspects of plant genomes were analyzed in the molecular level. The structure and organization of chloroplast DNA from Oryza species have been studied, and deletions which were the result of intramolecular recombination mediated by short direct-repeat sequences were found. This type of variation existed within a single species. It has been known that the mitochondrial genome of higher plant is largest and most complex among those of eukaryotes. The complexity of the genome is enhanced by the existence of chloroplast sequences in the genome. The entire set of transferred chloroplast DNA sequences in the mitochondrial genome from rice was identified and sequenced. Sixteen chloroplast sequences, ranging from 32 bases to 6.8 kb in length, were found to be dispersed throughout the rice mitochondrial genome. The transfers of segments of chloroplast DNA seem to have occurred at different times, both before the divergence of rice and maize and after this divergence. Small repeated sequences (from 60 to 66 basepairs in length)have been identified in the mitochondrial genome of rice. There are atleast ten copies of these sequences and thety are distributed throughout the mitochondrial genome. Each is potentially capable of forming a stem-and-loop structure and have been designated PRS(Palindromic Repeated Sequences). It was found that homologous recombinatio mediated by two PRSs occurred in the mtDNA of Oryza after divergence of the BB genome-type and the other genome-types of Oryza.The origins and the phylogenetic relationships between diploid and polyploid wheats have studied using molecular genetic methods. The results show the evolution of the genome mainly depends on changes in the untranslated regions of the DNA,and the evolutional rates of coding sequences are low.

从分子水平上分析了植物基因组的动态特征。对水稻属植物叶绿体DNA的结构和组织进行了研究，发现了短重复序列介导的分子内重组所致的缺失。这种类型的变异存在于单一物种中。高等植物的线粒体基因组是真核生物中最大、最复杂的基因组。基因组中叶绿体序列的存在增加了基因组的复杂性。对水稻线粒体基因组中转移的全套叶绿体DNA序列进行了鉴定和测序。在水稻线粒体基因组中发现了16个长度从32个碱基到6.8 kb不等的叶绿体序列。叶绿体DNA片段的转移似乎发生在不同的时间，无论是在水稻和玉米分化之前和这次分化之后。在水稻线粒体基因组中已经发现了小的重复序列(长度从60到66个碱基)。这些序列至少有10个拷贝，分布在整个线粒体基因组中。每一种都有可能形成茎环结构，并被指定为回文重复序列(Prindroic Repeat Sequence)。发现水稻BB基因组类型与其他基因组类型分化后，线粒体DNA发生了由两个PRSS介导的同源重组。用分子遗传学方法研究了二倍体和多倍体小麦的起源和系统发育关系。结果表明，基因组的进化主要依赖于DNA非翻译区的变化，编码序列的进化速率较低。