CAJ | 학술논문

重复DNA沿染色体的分布是认识植物基因组的组织和进化的要素之一.本研究采用一种改良的基因组原位杂交程序,对基因组大小和重复DNA数量不同的6种植物进行了自身基因组原位杂交(self-genomic in situ hybridization,self-GISH).在所有供试物种的染色体都观察到荧光标记探针DNA的不均匀分布.杂交信号图型在物种间有明显的差异,并与基因组的大小相关.小基因组拟南芥的染色体几乎只有近着丝粒区和核仁组织区被标记.基因组相对较小的水稻、高粱、甘蓝的杂交信号分散分布在染色体的全长,但在近着丝粒区或近端区以及某些异染色质臂的分布明显占优势.大基因组的玉米和大麦的所有染色体都被密集地标记,并在染色体全长显示出强标记区与弱标记或不标记区的交替排列.此外,甘蓝染色体的所有近着丝粒区和核仁组织区、大麦染色体的所有近着丝粒区和某些臂中间区还显示了增强的信号带.大麦增强的信号带带型与其N-带带型一致.水稻自身基因组原位杂交图型与水稻Cot-1 DNA在水稻染色体上的荧光原位杂交图型基本一致.研究结果表明,自身基因组原位杂交信号实际上反映了基因组重复DNA序列对染色体的杂交,因而自身基因组原位杂交技术是显示植物基因组中重复DNA聚集区在染色体上的分布以及与重复DNA相关联的染色质分化的有效方法.
중복DNA연염색체적분포시인식식물기인조적조직화진화적요소지일.본연구채용일충개량적기인조원위잡교정서,대기인조대소화중복DNA수량불동적6충식물진행료자신기인조원위잡교(self-genomic in situ hybridization,self-GISH).재소유공시물충적염색체도관찰도형광표기탐침DNA적불균균분포.잡교신호도형재물충간유명현적차이,병여기인조적대소상관.소기인조의남개적염색체궤호지유근착사립구화핵인조직구피표기.기인조상대교소적수도、고량、감람적잡교신호분산분포재염색체적전장,단재근착사립구혹근단구이급모사이염색질비적분포명현점우세.대기인조적옥미화대맥적소유염색체도피밀집지표기,병재염색체전장현시출강표기구여약표기혹불표기구적교체배렬.차외,감람염색체적소유근착사립구화핵인조직구、대맥염색체적소유근착사립구화모사비중간구환현시료증강적신호대.대맥증강적신호대대형여기N-대대형일치.수도자신기인조원위잡교도형여수도Cot-1 DNA재수도염색체상적형광원위잡교도형기본일치.연구결과표명,자신기인조원위잡교신호실제상반영료기인조중복DNA서렬대염색체적잡교,인이자신기인조원위잡교기술시현시식물기인조중중복DNA취집구재염색체상적분포이급여중복DNA상관련적염색질분화적유효방법.
The distribution of repetitive DNAs along chromosomes is one of the crucial elements for understanding the organization and the evolution of plant genomes. Using a modified genomic in situ hybridization (GISH) procedure, fluorescence in situ hybridization (FISH) with genomic DNA to their own chromosomes (called self-genomic in situ hybridization, self-GISH) was carried out in six selected plant species with different genome size and amount of repetitive DNA. Nonuniform distribution of the fluorescent labeled probe DNA was observed on the chromosomes of all the species that were tested. The signal patterns varied among species and were related to the genome size. The chromosomes of the small Arabidopsis genome were labeled almost only in the pericentromeric regions and the nucleolus organizer regions (NORs). The signals in the relatively small genomes, rice, sorghum,and Brassica oleracea var. capitata L., were dispersed along the chromosome lengths, with a predominant distribution in the pericentromeric or proximal regions and some heterochromatic arms. All chromosomes of the large genomes, maize and barley,were densely labeled with strongly labeled regions and weakly labeled or unlabeled regions being arranged alternatively throughout the lengths. In addition, enhanced signal bands were shown in all pericentromeres and the NORs in B. oleracea var. capitata, and in all pericentrometic regions and certain intercalary sites in barley. The enhanced signal band pattern in barley was found consistent with the N-banding pattern of this species. The GISH with self-genomic DNA was compared with FISH with Cot-1 DNA in rice,and their signal patterns are found to be basically consistent. Our results showed that the self-GISH signals actually reflected the hybridization of genomic repetitive DNAs to the chromosomes, thus the self-GISH technique would be useful for revealing the distribution of the regions where repetitive DNAs concentrate along chromosomes and some chromatin differentiation associated with repetitive DNAs in plants.