Human genetic engineering to erase disease-producing genes has not found clinical use because the success rate is low and the possibility of unintended consequences unacceptably high. But in a project led by Shoukhrat Mitalipov, a new technique using the CRISPR-Cas9 tool has been used to improve on the hit rate. It enjoyed considerable success in eliminating a strand of DNA in sperm encoding for a heart condition which kills suddenly, often at a young age. Anxieties about eugenics will soon follow, but they are misplaced.
Technically, nothing very new has happened. The CRISPR locus of the gene has been known since the 1980s, when it was identified as the defender of single-cell organisms against viruses. It was forged into a genetic engineering tool in this decade, and is being used by researchers in countries like Sweden, the UK and China, to replace short DNA sequences with genetic material of their choice. Mitalipov’s team innovated a new lab technique but while the pathological DNA was excised, it was not replaced by the strand the scientists had anticipated. In effect, this means that the method cannot be used to guarantee fair-skinned, blond-haired babies with little biceps bulging between their phalanges.
What it does mean, however, is that when it is accurate enough for clinical use, the method can advance eugenics in a positive manner, by eliminating hereditary disability and disease. It can reduce suffering on a grand scale, erasing a range of diseases from mitochondrial disorder, which strikes in the nursery, to Huntington’s chorea, which destroys the brain in middle age. Once the success rate is acceptable and the unintended consequences of “off-site mutations” reduced, techniques using the CRISPR locus are bound to become standard interventions, like paediatric shots are today. This is the future of human evolution and should be embraced — with regulation, of course.