Quentin Y
CNRS-LCB, UPR 7221, Marseille, France.
Nucleic Acids Res. 1994 Jun 25;22(12):2222-7. doi: 10.1093/nar/22.12.2222.
The question of the origin of the B1 family of rodents is addressed. The modern B1 elements are similar to the left Alu monomer, but with a 9 bp deletion and a 29 bp duplication. Search of databases for B1 elements that do not exhibit those modern features revealed sequence fragments that are very similar to the free left Alu monomers (FLAMs) described in the primate genomes. In addition, the analysis reveals elements that have 10 bp or 7 bp deletion in place of the 9 bp deletion but without the 29 bp tandem duplication. The elements described define families of proto B1 elements (referred as PB1, PB1D10 and PB1D7) that appeared before the first modern B1 element. A phylogenetic reconstruction suggest that the origin of Alu and B1 families took place before the divergence between the primate and the rodent lineages and that each family has followed different evolutionary routes since this radiation.
本文探讨了啮齿动物B1家族的起源问题。现代B1元件与左侧Alu单体相似，但有一个9bp的缺失和一个29bp的重复。在数据库中搜索不具有这些现代特征的B1元件，发现了与灵长类基因组中描述的游离左侧Alu单体（FLAMs）非常相似的序列片段。此外，分析还发现了一些元件，它们有10bp或7bp的缺失来取代9bp的缺失，但没有29bp的串联重复。所描述的这些元件定义了原始B1元件家族（称为PB1、PB1D10和PB1D7），它们出现在第一个现代B1元件之前。系统发育重建表明，Alu和B1家族的起源发生在灵长类和啮齿类谱系分化之前，并且自这次辐射以来，每个家族都遵循了不同的进化路线。
