3种滨海碱蓬属植物串联重复序列与转座元件比较分析

    Comparative Analysis of Tandem Repeats and Transposable Elements in Three Coastal Suaeda Species

    • 摘要: 为了解析3种常见的滨海碱蓬属物种的重复序列类型、丰度、染色体分布模式及种间差异,采用基于序列相似性聚类分析和荧光原位杂交技术,对它们的重复序列进行比较分析。结果表明:3个物种中均存在串联重复序列和转座元件。其中,端粒序列、5S rDNA、35S rDNA为3个物种保守的串联重复序列,另外有2个串联重复序列是碱蓬中特异的,这些串联重复序列倾向于在染色体端粒、亚端粒、染色体臂富集。此外,3个碱蓬属物种的转座元件主要由反转录转座子和DNA转座子组成,其中Ty3/gypsy反转录转座子的基因组占比较高,而Ty1/copia反转录转座子和DNA转座子的基因组含量则相对较低。除了CRM谱系主要在着丝粒区域聚集,大多数转座元件在染色体上呈现散布分布,而一些基因组丰度较低的转座元件则未检测到信号。根据重复序列和染色体分布分析结果表明,与碱蓬相比,南方碱蓬和盐地碱蓬的基因组关系更近。这些发现将为理解3种滨海碱蓬属物种重复序列的特征和种间进化关系提供了依据。

       

      Abstract: In order to analyze the types, abundance, chromosomal distribution patterns, and interspecific differences of repetitive sequences in three common species of coastal Suaeda, the sequence similarity-based clustering analysis and fluorescence in situ hybridization techniques were used for the comparative analysis of their repetitive sequences. The results revealed that there were tandem repeats and transposable elements in all the three species. Among them, the telomeric sequences, 5S rDNA, and 35S rDNA were identified as the conserved tandem repeats across the three species, while the other two tandem repeats were identified as being specific to Suaeda glauca. These tandem repeats tended to be enriched in the chromosome telomeres, subtelomeres, and chromosomal arms. Furthermore, the transposable elements in the three Suaeda species were mainly composed of retrotransposons and DNA transposons. Notably, the genome of Ty3/gypsy retrotransposons were found to have a higher genomic proportion, while the Ty1/copia retrotransposons and DNA transposons were relatively less abundant. Except for the CRM lineage, which was mainly clustered in the centromeric region, most of transposable elements exhibited a dispersed distribution across the chromosomes, while some transposable elements with lower genomic abundance were not detected. According to the analysis results of repetitive sequence and chromosomal distribution, the genomic relationship between Suaeda australis and Suaeda salsa was closer than that of Suaeda glauca. These findings would provide a basis for understanding the characteristics of repetitive sequences and the evolutionary relationships among the three species of coastal Suaeda.

       

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