Tag: CRISPR

Science Sunday: Gene Editing

Genetic engineering has been with us for about forty years. During that time, it has helped us develop more effective drugs, drought- and disease-resistant crops, and a barrage of genetic tests that can measure your risk for such things as breast cancer. It has also sparked a lot of opposition from those who fear its power as well as luddite hatred from anti-GMO types who have successfully slowed the implementation of such as things as “the golden rice” and therefore condemned thousands of children to unnecessary blindness.

Things took another step a couple of weeks ago, however, when researchers in China used the new CRISPR technology to modify the genes of non-viable human embryos. Does this mean we are on the verge of a real-life Gattaca? Should we be worried about this?

Francis Collins, the NIH Director, makes the case against allowing this kind of research:

It’s also very hard to identify the need for this kind of embryo manipulation for human purposes. If you’re talking about genetic disease, we have pre-implantation genetic diagnosis, which gives couples at risk for genetic disease a chance to avoid that risk without any manipulation of the germline.

Last, there are deep concerns of a philosophical sort, about what it means for human beings to intentionally manipulate their own genomes. If applied broadly and widely, does that result in us being changed into something other than homo sapiens? I don’t think we even have to go to that one to say this is something we shouldn’t do. The safety arguments and lack of medical need trump [these concerns].

Collins gets one thing very wrong in that paragraph: his claim that pre-implantation diagnosis is enough for couples screening for genetic disease. We looked into this when we were doing fertility treatments (Hal 11000 Beta came about the old-fashioned way after fertility failed). Our doctor told us that the diagnosis tech is shaky at best. And with some disorders — such as Down’s — the errors can occur in some cells but not others. So the idea that there is no “need” for this — even assuming we have to show a need to the likes of Collins — is a bit of a reach.1

But Collins hits most of the points probably going through your head: that this kind of research would be unethical, that messing with the human genome is a dangerous road, etc.

The counterpoint is given by Ramez Naan at Marginal Revolution in two posts (here and here).

[Banning this research] is a mistake, for several reasons.

1. The technology isn’t as mature as reported. Most responses to it are over-reactions.

2. Parents are likely to use genetic technologies in the best interests of their children.

3. Using gene editing to create ‘superhumans’ will be tremendously harder, riskier, and less likely to be embraced by parents than using it to prevent disease.

4. A ban on research funding or clinical application will only worsen safety, inequality, and other concerns expressed about the research.

Part 1 I didn’t find terribly interesting. He’s right that CRISPR can’t create viable genetically modified embryos. But the ethical issues remain. Someday, we probably will have that power.

His other points are much more germane. He points out the human genome, like almost everything in the human body, has many moving parts. There is no single gene for high intelligence or good looks. You would have to make massive changes to many parts of someone’s DNA to, say, make them taller. This is why short parents can have tall kids and vice versa — the genetics are far more complex than, say, hair color.

Manipulating IQ, height, or personality is thus likely to involve making a very large number of genetic changes. Even then, genetic changes are likely to produce a moderate rather than overwhelming impact.

Conversely, for those unlucky enough to be conceived with the wrong genes, a single genetic change could prevent Cystic Fibrosis, or dramatically reduce the odds of Alzheimer’s disease, breast cancer or ovarian cancer, or cut the risk of heart disease by 30-40%.

Reducing disease is orders of magnitude easier and safer than augmenting abilities.

That addressed Collins’ major point. There is a medical need for this sort of technology; a big one. One that could be filled very easily and at low risk.

Now, it’s possible we could one day have the technology to modify more complex things like height or intelligence. But that technology is decades away at this point, even assuming it is possible at all. It would require an understanding of genetics, and possibly even more importantly, epigenetics, that is a quantum leap beyond where we are now. It’s something to worry about, but not if its means blocking technology that could cure Cystic Fibrosis.

Naam’s third point is that parents are risk-averse. This plays on the first point. Parents might, in theory, want to give their child a genetic leg up. But the best they might face is a possibility of increasing their child’s IQ by ten points at the potential risk of unknown disorders or complications. While I agree with him, it’s certain that some parents will embrace these risks, especially as the technology matures.

Naam’s final point is basically that this is going to happen. And once it does, there is no putting the genie back in the bottle. If we ban it here, it will pop up in China. If we get China to ban it, it will pop up in India. If we get India to ban it, it will pop up in South Africa.

This is not something we can unlearn. It’s something we have to deal with. At this stage, given the crudeness of the technology, I am more than happy for the NIH to ban research into genetically engineering humans. But that’s kicking the can down the road. At some point, we will have to decide what we will and will not allow and who gets to decide what risks are and are not worth it.

We have, however, been here before. In the 1970’s, there were efforts to ban the very genetic engineering that has been so beneficial to us and brought us to this point. Supporters of the ban included James Watson, one of the discoverers of DNA’s structure, and Al Gore, supposed science luminary (Watson later admitted he was wrong). They failed, barely. And as it turned out, it was for the best. As P.J. O’Rourke noted twenty years ago in All the Trouble in the World:

Biotechnologists could still come up with something awful by accident, not to mention on purpose. Nature does it all the time. Nature is forever inventing things like the bubonic plague, although whether intentionally or not is a question too deep for this state college graduate. But, in the meantime, we’ve got a four-billion-dollar biotech industry that produces cheap insulin, accurate tests for everything from pregnancy to colon cancer, new vaccines, the diagnostic process that keeps the nation’s blood supply freed of AIDS and hepatitis, and hundreds of other products, with thousands more on the horizon — a small price to pay for an occasional giant sheep.

Nature is forever editing the human genome. The possibility of humans tampering with their own genetics is frightening and I think we should take the potential risks seriously. But, given history, it is much more likely to result in the ability to cut the risk of cancer than to produce a race of Uma Thurman clones.

Genetic engineering did play one role in Hal’s birth. Thanks to a new genetic screening technique, we were able to test Hal at ten weeks for potential trisomies with 99% accuracy.</sup