Germline edit­ing of hu­man em­bryos is need­less, danger­ous, and un­eth­i­cal

The Guardian - Journal - - News -

The Crispr/Cas9 tech­nique of edit­ing DNA is, by the stan­dards of ear­lier meth­ods, as­ton­ish­ingly quick and easy. It is not en­tirely re­li­able or accurate, but it places enor­mous po­ten­tial power in the hands of or­di­nary sci­en­tists. It is also in­ter­na­tion­ally wide­spread, and beyond the con­trol of any sin­gle na­tion now. So reck­less and un­eth­i­cal ex­per­i­ments were only to be ex­pected; nonethe­less, last week’s an­nounce­ment by a Chi­nese sci­en­tist that he had al­tered the germlines of twin girls to mod­ify a gene in­volved in the trans­mis­sion of HIV was a pro­foundly wor­ry­ing one, for sev­eral reasons.

The most im­por­tant is that there is no med­i­cal rea­son for what he did. There is a vi­tally im­por­tant dif­fer­ence be­tween edit­ing the genes which are present in a body and those which are present in sperm or eggs. With the first kind of mod­i­fi­ca­tions, the ef­fects die with the bearer. With the sec­ond, they are passed, like mu­ta­tions, down into fu­ture gen­er­a­tions. Of course such mu­ta­tions might in the­ory be en­tirely ben­e­fi­cial. But sci­en­tists don’t at the mo­ment have nearly enough knowl­edge to judge whether this is true or even prob­a­ble in prac­tice. They’d need to know at least how any par­tic­u­lar mod­i­fied gene will per­form over a life­time, and, ide­ally, what ef­fects it might have in sub­se­quent gen­er­a­tions.

For those few gene vari­a­tions where the ev­i­dence is en­tirely clearcut, there is al­most al­ways the pos­si­bil­ity of test­ing em­bryos pro­duced by IVF and im­plant­ing those which lack the fa­tal de­fect. That is al­ready widely prac­ticed in the rich world by cou­ples at risk, and is not very con­tro­ver­sial. Although dis­abil­ity ac­tivists are con­cerned about the risk that some con­di­tions like Down’s syn­drome might be elim­i­nated en­tirely by such means, there are other, much rarer, and more cruel con­di­tions which make the short lives of af­fected ba­bies un­bear­able both for them and for any­one who loves them.

But there is no need for Crispr ma­nip­u­la­tions to achieve this. What Dr He at­tempted was far more am­bi­tious. He took em­bryos which were – so far as we know – en­tirely nor­mal, but whose fa­thers were suf­fer­ing from HIV, and al­tered one of their genes with par­tial and patchy suc­cess into a form which seems to be re­spon­si­ble for the im­mu­nity that some Euro­peans ap­pear to have to the virus.

These ba­bies were not oth­er­wise in any greater dan­ger of catch­ing the virus than any­one else.

Their moth­ers are not in­fected. Although he spoke at his pre­sen­ta­tion of the prospect of elim­i­nat­ing the dis­ease from Africa by these means, this is a fan­tasy. Very much cheaper and more ef­fec­tive meth­ods of com­bat­ing the dis­ease are al­ready avail­able.

The ob­sta­cles to their de­ploy­ment are war, poverty and cor­rup­tion, not lack of sci­ence.

It’s very dif­fi­cult to un­der­stand this story as any­thing other than a piece of sci­en­tific hubris, more driven by the de­sire to ex­per­i­ment than by real com­pas­sion. But although it has been roundly con­demned by gen­uinely distin­guished sci­en­tists such as Dr Fran­cis Collins, it is un­likely to be the last such ex­per­i­ment. Gene ther­apy used once to be de­nounced as “play­ing God”. That is no rea­son to aban­don it. But if hu­mans are to play God, they need to be­have in a morally bet­ter way than un­aided na­ture does. Evo­lu­tion it­self might be de­scribed as a vast pro­gramme of ge­netic ex­per­i­ments con­ducted with no re­gard for the cost or con­se­quences. If hu­man be­ings are to take con­trol of the process – and gene edit­ing al­lows them at least to af­fect it – we must learn to take into ac­count both cost and con­se­quence, and to use our new powers re­spon­si­bly.

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