HOW DOES IT WORK?

摘要

The first forms of genetic engineering involved adding extra bits of DNA to the genomes of plants and animals, with no control over where they ended up, One method involved shooting bullets coated with DNA at cells. Gene editing, in contrast, adds DNA to precise spots in a genome, or alters a specific sequence, so is far superior. While a few methods of gene editing had been developed, until the advent of CRISPR, it was usually slow, difficult and very expensive. CRISPR targets a particular DNA sequence using a piece of RNA that's complementary to that DNA. Linked to it is a protein derived from bacteria, called Cas9. The RNA finds the right bit of DNA and binds to it, then Cas9 cuts it (see diagram, right). The cell's repair mechanisms will re-join the two pieces, but in the process the DNA sequence gets slightly altered, This is how genes can be disabled.