A box containing viles of human embryonic Stem Cell cultures Sandy Huffaker/Getty Images

The Holy Grail of Genetic Engineering

CRISPR-Cas – a gene-editing technique that is far more precise and efficient than any that has come before it – is poised to change the world. But ensuring that those changes are positive – helping to fight tumors and mosquito-borne illnesses, for example – will require scientists to apply the utmost caution.

HONG KONG – Since its introduction four decades ago, genetic engineering has been a source of high hopes for health, agriculture, and industry. But it has also provoked deep anxiety, not least owing to the laborious nature of the genome-editing process. Now, a new technique, CRISPR-Cas, offers both precision and the ability to modify the genome text at several places simultaneously. But this has not eliminated reason for concern.

The genome can be viewed as a kind of musical score. Just as sheet music tells musicians in an orchestra when and how to play, the genome tells the cell’s component parts (generally proteins) what they must do. A score may also include notes from the composer, showing possible changes, frills that can be added or omitted depending on the circumstances. For the genome, such “notes” emerge from cell survival over many generations in an ever-changing environment.

The DNA genetic program is akin to a fragile book: the order of its pages can change, with some even being moved to another cell’s program. If a page is, say, laminated, it is less likely to be damaged as it is moved around. Likewise, elements of a genetic program protected by a solid coating are better able to invade a variety of cells, and then to reproduce as the cell reproduces.