Time to Think Carefully _ the Economist
Click here to load reader
description
Transcript of Time to Think Carefully _ the Economist
![Page 1: Time to Think Carefully _ the Economist](https://reader038.fdocuments.in/reader038/viewer/2022100502/577c7ec11a28abe054a2507f/html5/thumbnails/1.jpg)
12/9/2015 Time to think carefully | The Economist
http://www.economist.com/node/21679434/print 1/2
Genetic engineering
Time to think carefullyAn international summit discusses the use of gene editing
Dec 5th 2015 | Washington, DC | From the print edition
“OVER the years the unthinkable has become
conceivable and today we sense we are close to
being able to alter human heredity.” These were
the words of David Baltimore of the California
Institute of Technology, on December 1st, when
he opened a threeday meeting in Washington to
discuss the ethics and use of human gene editing.
Dr Baltimore is an old hand at these sorts of
discussions, for he was also a participant in the Asilomar conference, in 1975, which brought
scientists together to discuss a safe way of using the thennew technology of recombinant DNA,
and whose recommendations influenced a generation of biotechnology researchers.
Four decades on, the need for a similar sort of chinwag has arisen. The International Summit
on Human Gene Editing has been convened by the national scientific academies of three
countries—America, Britain and China. They are particularly concerned about whether gene
editing should be used to make heritable changes to the human germ line, something Dr
Baltimore described as a deep and troubling question. Like those of Asilomar, the conclusions of
this meeting, which was due to end after The Economist went to press, will not be binding. But
the hope is that, again like Asilomar, a mixture of common sense and peer pressure will create a
world in which scientists are trusted to regulate themselves, rather than having politicians and
civil servants do it for them.
The meeting is being held against a backdrop of rapid scientific advance. Since 2012 research
into a new, easytouse editing tool called CRISPRCas9 has blossomed. This technique involves
a piece of RNA (a chemical messenger, which can be used to recognise a target section of DNA)
and an enzyme called a nuclease that can snip unwanted genes out and paste new ones in.
Public interest was aroused in April, when Chinese scientists announced they had edited genes
![Page 2: Time to Think Carefully _ the Economist](https://reader038.fdocuments.in/reader038/viewer/2022100502/577c7ec11a28abe054a2507f/html5/thumbnails/2.jpg)
12/9/2015 Time to think carefully | The Economist
http://www.economist.com/node/21679434/print 2/2
in nonviable human embryos, and again in November when British researchers said they had
successfully treated a oneyearold girl who had leukaemia, using geneedited Tcells. Tcells
are part of the immune system that attack, among other things, tumour cells. The researchers
altered Tcells from a healthy donor to encourage them to recognise and kill the patient’s
cancer, to make them immune to her leukaemia drug, and to ensure they did not attack her
healthy cells.
In another recent development, a firm called Editas Medicine, which is based in Cambridge,
Massachusetts, has said it hopes, in 2017, to start human clinical trials of CRISPRCas9 as a
treatment for a rare genetic form of blindness known as Leber congenital amaurosis. Though
other companies are already testing geneediting therapies, these employ older, clunkier forms
of the technology that seem likely to have less commercial potential. Moreover, researchers at
the Broad Institute, also in Cambridge, said this week that they had made changes to CRISPR
Cas9 which greatly reduce the rate of editing errors—one of the main obstacles to the
technique’s medical use.
On the subject of germline editing, Eric Lander, the Broad’s head, told the meeting it would be
useful only in rare cases and said it might be a good idea to “exercise caution” before making
permanent changes to the gene pool. The need for caution is advice that might also be heeded
by those pursuing work in animals other than people, and in plants—subjects not being covered
by the summit.
Last month, researchers at the University of California, Irvine, said they had used CRISPRCas9
to build what is known as a “gene drive” in mosquitoes. Gene drives can copy themselves and
their associated gene directly into chromosomes that do not have them, meaning that all
offspring of an organism will inherit a chromosome bearing the gene in question. This ensures
the gene spreads through the population, even if it does not confer advantages. In mosquitoes,
the idea is to spread genes that would make them resistant to the parasite that causes malaria.
But some researchers worry that, once released into the wild, gene drives could induce
unpredictable and irreversible effects. Whatever the outcome of this week’s meeting, the debate
over gene editing is only just beginning.
From the print edition: Science and technology