Boston University bio-ethicist George Annas discusses the ethical issues raised by new gene-editing tools that may eventually allow humankind to control its own genetic legacy. (Courtesy)
The powerful new gene-editing tool CRISPR is sparking excitement in biology labs — but also calls for a broad discussion about limits, and whether we should ever meddle with the human gene pool. I asked Boston University bio-ethicist Prof. George Annas for his take. Our conversation, edited:
CG: So scientists are saying we should start talking about using CRISPR to alter the human gene pool. What would a conversation like that even sound like?
GA: The conversation is not about CRISPR per se. It’s about: Now that we have techniques to edit the human genome, should we edit the human genome, and if so, for what purposes?
We’ve had this conversation around cloning in the mid-1990s. Most but not all scientists, and almost everyone in the public, agreed we should not try to clone a human being, use our genetic knowledge to make a genetic duplicate human being. And we’ve had very good luck: it’s turned out not to be possible to clone a human being. At least, we don’t know how to do it yet.
But with CRISPR, it seems much more likely that sometime in the not-too-distant future — though it may be decades, this gene editing technology will be dependable enough that someone is likely to try to use it on a human embryo.
This will be a big and dangerous step—dangerous for sure to the resulting child. Many people have no trouble with using genome editing on animals and plants, so long as you’re not harming the animal in a way that makes it suffer. But children do suffer. So the first question is: Should we ever try to edit the genomes of human embryos that are destined to become children? I think the answer is no.
I agree with the scientists who say that it’s definitely not safe to do it now because we can’t predict what other things CRISPR will do to the rest of the genome. We know very little about the genome, and what impact taking out one or a series of base pairs — with CRISPR, you can take a series out — is going to do to the rest of the genome, and hence to the whole organism as it develops.
And the problem with germ-line genetic engineering at the level of the embryo —
— Making genetic changes that will be passed on forever —
Potentially, yes. First they will be passed on to this baby, and this baby will become an adult. And if this “engineered” baby has children, the new traits will be passed on to the next generation, and so on.
So an initial question — and scientists agree with this — is, how many generations do you need to prove that a particular method of genome editing is safe? I would guess most scientists would say, at least four or five. Well, we can do four or five generations in zebrafish or in rats or in fruit flies pretty quickly.. In humans, however, it’s going to take you probably 100 years. So, how many children would you want to follow, and their offspring, for 100 years before you are ready to conclude that editing the human genome is safe for children?
That strikes me as a question that we can’t answer. Because we cannot prove it safe without putting human children at terrible risk of harm, we can’t subject any human child to this experiment. That’s because children can’t consent, and their consent is necessary as a matter of ethics because there are good reasons to anticipate that something will go horribly wrong.
And more broadly, there are potential implications for the whole human race, if we start engineering evolution — ? Continue reading