CAJ | 학술논문

本研究对苏铁(Cycas revoluta)nrDNA ITS进行克隆测序,并以cDNA ITS为参照,比较分析获得的序列的碱基变异、GC含量、5.8S二级结构的稳定性和5.8S保守基序的有无以及系统发育关系.结果发现苏铁nrDNA ITS存在较高的基因组内多样性,同时,这些分化的nrDNA ITS拷贝中包含有假基因的存在,而且假基因与功能拷贝之间已经形成了较大的遗传分化,这暗示假基因起源有较长历史.苏铁核仁组织区不仅多达16个,而且分布在13条染色体上,这可能是其nrDNA ITS致同进化不完全的主要原因.
본연구대소철(Cycas revoluta)nrDNA ITS진행극륭측서,병이cDNA ITS위삼조,비교분석획득적서렬적감기변이、GC함량、5.8S이급결구적은정성화5.8S보수기서적유무이급계통발육관계.결과발현소철nrDNA ITS존재교고적기인조내다양성,동시,저사분화적nrDNA ITS고패중포함유가기인적존재,이차가기인여공능고패지간이경형성료교대적유전분화,저암시가기인기원유교장역사.소철핵인조직구불부다체16개,이차분포재13조염색체상,저가능시기nrDNA ITS치동진화불완전적주요원인.
In the present study, a high intra-genomic polymorphism was detected in the internal transcribed spacer (including ITS1, 5.8S and ITS2) regions of Cycas revoluta, suggestive of incomplete concerted evolution. Detailed comparisons of the ITS sequences from C. revoluta and those from other species further suggested that some divergent ITS paralogs from C. revoluta were likely pseudogenes. Some of these putative pseudogenes may have rather long evolutionary histories, because they have diverged substantially in sequences. We proposed that the incomplete concerted evolution in C. revoluta may have resulted from the high number and dispersed distribution of the nucleolus organizer regions (NORs) in the genome.