= Genome editing
<Genome editing> deliberately changes the <DNA> sequence at selected sites in a <genome>. Changes can include a small insertion or deletion, replacement of a sequence, or introduction of a specific base change. This differs from merely measuring <gene expression> or transiently changing it without altering the underlying <DNA>.
In a common <CRISPR-Cas9> approach, a guide <RNA> directs a <nuclease> to a matching <DNA> region, and cellular <DNA repair> determines the resulting sequence change. Repair can disrupt a <gene> or use a supplied template to introduce a designed change. <Le Cong> and colleagues demonstrated programmable targeting of endogenous mammalian sites and simultaneous editing at several sites in 2013.<Multiplex genome engineering using CRISPR Cas systems by Le Cong and others>[Abstract and Results: endogenous loci, repair pathways and multiplex targeting]{ref}
A targeted cut is therefore an intermediate operation, not proof of the intended edit. <DNA sequencing> of the resulting <alleles> distinguishes the planned change from unintended repair products.
Back to article page
