Kordis D, Gubensek F
Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Ljubljana, Slovenia.
Toxicon. 1998 Nov;36(11):1585-90. doi: 10.1016/s0041-0101(98)00150-0.
In the fourth intron of two toxic Vipera ammodytes PLA2 genes a Ruminantia specific 5'-truncated Bov-B LINE element was identified. Southern blot analysis of Bov-B LINE distribution in vertebrates shows that, apart from the Ruminantia, it is limited to Viperidae snakes (V. ammodytes, Vipera palaestinae, Echis coloratus, Bothrops alternatus, Trimeresurus flavoviridis and Trimeresurus gramineus). The copy number of the 3' end of Bov-B LINE in the V. ammodytes genome is between 62,000 and 75,000. At orthologous positions in other snake PLA2 genes the Bov-B LINE element is absent, indicating that its retrotransposition in the V. ammodytes PLA2 gene locus has occurred quite recently, about 5 Myr ago. The amplification of Bov-B LINEs in snakes may have occurred before the divergence of the Viperinae and Crotalinae subfamilies. Due to its wide distribution in Viperidae snakes it should be a valuable phylogenetic marker. The neighbour-joining phylogenetic tree shows two clusters of truncated Bov-B LINE, a Bovidae and a snake cluster, indicating an early horizontal transfer of this transposable element.
在两种有毒的极北蝰蛇PLA2基因的第四内含子中，鉴定出一种反刍亚目特异性的5'-截短的Bov-B LINE元件。对脊椎动物中Bov-B LINE分布的Southern印迹分析表明，除反刍亚目外，它仅限于蝰蛇科蛇类（极北蝰、巴勒斯坦蝰蛇、彩蝰、阿根廷矛头蝮、竹叶青和绿竹叶青）。极北蝰蛇基因组中Bov-B LINE 3'端的拷贝数在62,000至75,000之间。在其他蛇PLA2基因的直系同源位置不存在Bov-B LINE元件，这表明它在极北蝰蛇PLA2基因座中的反转录转座发生得相当晚，大约在500万年前。蛇类中Bov-B LINEs的扩增可能发生在蝰蛇亚科和响尾蛇亚科分化之前。由于其在蝰蛇科蛇类中的广泛分布，它应该是一个有价值的系统发育标记。邻接法系统发育树显示出两个截短的Bov-B LINE簇，一个牛科簇和一个蛇簇，表明这种转座元件的早期水平转移。
