Batistoni R, Pesole G, Marracci S, Nardi I
Laboratori di Biologia Cellulare e dello Sviluppo, Dipartimento di Fisiologia e Biochemica, Pisa, Italy.
J Mol Evol. 1995 Jun;40(6):608-15. doi: 10.1007/BF00160508.
We have characterized a highly repetitive family, named Hy/Pol III, in the genome of the European salamanders Hydromantes (Plethodontidae). This family consists of short, tandemly repeated sequences organized in clusters, scattered through the genome as shown both by in situ hybridization to chromosomes and by Southern blot hybridization. The repeat unit is about 200 bp in length and it is a composite element since it contains a SINE-like retroposon with a tRNA structure, flanked by two short direct repeats. The whole element itself is bordered by two other direct repeats. The sequence data suggest that two elements, presumably derived from polymerase III transcripts, have been inserted one into the other, giving rise to the observed composite structure. During evolution the Hy/Pol III family was then amplified by tandem duplication at the DNA level. The inferred relationships between Hy/Pol III members from three representative species of the European Hydromantes suggests that a subfamily structure characterizes the evolutionary history of this family.
我们在欧洲蝾螈Hydromantes（无肺螈科）的基因组中鉴定出了一个高度重复的家族，命名为Hy/Pol III。这个家族由短串联重复序列组成，这些序列成簇排列，通过染色体原位杂交和Southern印迹杂交表明，它们分散在整个基因组中。重复单元长度约为200 bp，它是一个复合元件，因为它包含一个具有tRNA结构的SINE样反转座子，两侧是两个短的直接重复序列。整个元件本身由另外两个直接重复序列界定。序列数据表明，两个可能源自聚合酶III转录本的元件相互插入，形成了观察到的复合结构。在进化过程中，Hy/Pol III家族随后通过DNA水平的串联重复进行扩增。来自欧洲Hydromantes三个代表性物种的Hy/Pol III成员之间的推断关系表明，亚家族结构是该家族进化历史的特征。
