X染色体为何富含L1移动元件

Preferential insertion into the late-replicating inactive X explains L1 accumulation in this chromosome Aurélien J. Doucet and Gael Cristofari Long interspersed element-1 (LINE-1 or L1) is an abundant mobile genetic element in the human genome. It propagates by copying its own RNA into DNA and inserting itself elsewhere in the genome, a process known as retrotransposition. Occasionally, L1 insertion disrupts a gene and causes disease (1). L1s are unevenly distributed across the genome, and their density in the X chromosome is roughly twice that in nonsex chromosomes (autosomes) (2). More than 25 years ago, geneticist Mary Lyon proposed that X-linked L1s are retained by selection because they help to spread X-chromosome inactivation. …