Alu family and its biological significance

The Alu family of short(~300 bp)interspersed elements(SINEs) is one of the most successful mobile genetic elements, having arisen to a copy number in excess of one million within primate genomes in the last 65 million years. The proliferation of these elements had a significant impact on the architecture of primate genomes. Now the functions of Alu elements are still unclear. It is speculated that Alu elements are involved in aspects of gene regulation, e.g. gene rearrangement, CpG methylation, alternative splicing of hnRNA, binding sites of transcription factors and hormone receptors, etc. At the same time, Alu family is an important research method in human population genetics, forensic, and oncology, etc. Additionally, Alu insertion, deletion and recombination led to many ancestor genetic diseases and cancers.