Last week, the Chinese scientist He Jiankui announced the birth of the first CRISPR baby (actually, twins). Two beautiful little Chinese girls, Lulu and Nana, came crying into the world as healthy as any other babies a few weeks ago’, He said in the first of five videos posted on to YouTube.
He’s claim is as yet unverified, but if true, it would signal a landmark moment in human genome-editing. It has also been widely met with outrage and condemned by scientists and ethicists worldwide.
CRISPR-Cas 9 is a technique, adapted from a naturally occurring in bacteria, that allows researchers to cut DNA at a specific point and hence to edit the genome. It holds great promise in the battle against many diseases and disorders, but our understanding of the technique, and of its consequences, is still in its infancy.
Most observers see He’s work as reckless and unethical, given the paucity of our knowledge. This has been exacerbated by the fact that he has published few details of his research, and it hs not been peer reviewed.
Much CRISPR research attempts to disable faulty genes producing conditions such as cystic fibrosis. He excised a normal gene called CCR5, which encodes a protein that allows HIV to enter a cell, to try to reduce the risk of a disease that neither child had. ‘This experiment exposes healthy normal children to risks of gene editing for no real necessary benefit’, observed Julian Savulescu, director of Oxford University’s Uehiro Centre for Practical Ethics.
Much of the criticism is to the point. There is a danger, though, that the specific condemnation of He’s approach could turn into a wider assault on the whole idea of genome editing.
For some critics, any interference with the genome is dangerous and ‘unnatural’. Particularly contentious is ‘germline’ editing. ‘Somatic therapies’ alter genes in an individual but do not affect his or her children. Germline therapies modify the genome in an egg, sperm or embryo; any changes are passed on to future generations. To burden future generations with possibly dangerous genomic alterations is, many argue, unconscionable.
Certainly, any alteration to the germline should be undertaken only with the greatest of care, and with far more knowledge than we currently possess. Hence the condemnation of He.
But the possibilities inherent in genome-editing techniques to help prevent and treat disorders, from cystic fibrosis to cancer, are tremendous. Refusing to alter the genome when one could to do so safely is also to affect the future. He’s work may be unethical, but there is nothing ethically superior in condemning future generations to terrible medical conditions if it were possible safely to eliminate them.
The image, of the crystal structure of the Cas9 gene-editing enzyme (light blue) in complex with an RNA guide (red) and its target DNA (yellow), comes via the Broad Institute of Harvard and MIT and the US National Institutes of Health.
A version of this article will appear in the Observer, 2 December 2018