Garcia-Fernàndez J, Bayascas-Ramírez J R, Marfany G, Muñoz-Mármol A M, Casali A, Baguñà J, Saló E
Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Spain.
Mol Biol Evol. 1995 May;12(3):421-31. doi: 10.1093/oxfordjournals.molbev.a040217.
Several DNA sequences similar to the mariner element were isolated and characterized in the platyhelminthe Dugesia (Girardia) tigrina. They were 1,288 bp long, flanked by two 32 bp-inverted repeats, and contained a single 339 amino acid open-reading frame (ORF) encoding the transposase. The number of copies of this element is approximately 8,000 per haploid genome, constituting a member of the middle-repetitive DNA of Dugesia tigrina. Sequence analysis of several elements showed a high percentage of conservation between the different copies. Most of them presented an intact ORF and the standard signals of actively expressed genes, which suggests that some of them are or have recently been functional transposons. The high degree of similarity shared with other mariner elements from some arthropods, together with the fact that this element is undetectable in other planarian species, strongly suggests a case of horizontal transfer between these two distant phyla.
在扁形动物三角真涡虫（Dugesia (Girardia) tigrina）中分离并鉴定了几个与水手元件相似的DNA序列。它们长度为1288 bp，两侧是两个32 bp的反向重复序列，并包含一个单一的339个氨基酸的开放阅读框（ORF），编码转座酶。该元件的拷贝数在单倍体基因组中约为8000个，构成了三角真涡虫中重复DNA的一个成员。对几个元件的序列分析表明，不同拷贝之间具有很高的保守性。它们中的大多数都有一个完整的ORF和活跃表达基因的标准信号，这表明它们中的一些是或最近是功能性转座子。与一些节肢动物的其他水手元件高度相似，以及在其他涡虫物种中检测不到该元件，这强烈表明这是这两个远缘门之间水平转移的一个例子。
