Kim J, Deininger P L
Department of Biochemistry and Molecular Biology, Louisiana State University Medical Center, New Orleans, USA.
J Mol Biol. 1996 Aug 23;261(3):322-7. doi: 10.1006/jmbi.1996.0464.
The rodent identifier (ID) family of repeats has amplified at an extremely high rate in the rat genome in recent evolutionary time, resulting in 130,000 copies per haploid genome. Statistical analyses support the grouping of 119 individual rat ID elements into four major and three minor subfamilies based on six diagnostic nucleotide positions. The consensus sequence of the oldest subfamily is identical to the ID region of the rat BC1 RNA gene, suggesting that the BC1 gene has dominated the early amplification of rat ID elements. The other six subfamilies share at least one diagnostic mutation in relation to the BC1 gene and show much less nucleotide sequence divergence, indicating that the recent large amplification of rat ID elements has been driven by another lineage of master gene(s) in the rat genome. This is consistent with the formation of a new lineage of master elements for ID amplification in rat. The formation of most rat ID elements appears to have occurred during the past three million years based on the results that four out of five randomly chosen ID elements are present only in the genome of one rat species and not in other closely related species.
在最近的进化时期，啮齿动物重复序列标识符（ID）家族在大鼠基因组中以极高的速率扩增，导致单倍体基因组中有130,000个拷贝。统计分析支持根据六个诊断性核苷酸位置将119个单独的大鼠ID元件分为四个主要亚家族和三个次要亚家族。最古老亚家族的共有序列与大鼠BC1 RNA基因的ID区域相同，这表明BC1基因主导了大鼠ID元件的早期扩增。其他六个亚家族与BC1基因相比至少有一个诊断性突变，并且核苷酸序列差异小得多，这表明大鼠ID元件最近的大量扩增是由大鼠基因组中另一个主基因谱系驱动的。这与大鼠中ID扩增的新主元件谱系的形成一致。根据随机选择的五个ID元件中有四个仅存在于一个大鼠物种的基因组中而不存在于其他密切相关物种的基因组中的结果，大多数大鼠ID元件的形成似乎发生在过去三百万年中。
