After Dolly the sheep was born, several groups announced they were going to clone people. A bizarre religious cult and a maverick fertility doctor even claimed success in the 2000s, but these claims have never been taken seriously. As far as we know, no clone of an adult human has yet been born, not least because we have struggled to create cloned human embryos.
CRISPR gene editing, by contrast, is relatively easy. It鈥檚 not the sort of thing anybody could do in their kitchen, but with sufficient money a small team of rogue biologists and IVF doctors could create the first gene edited baby right now. 鈥淭his is the thing that scares me the most,鈥� says Robin Lovell-Badge of the Francis Crick Institute.
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In fact, there is nothing to stop IVF clinics trying germline gene editing in many countries, including the US. 鈥淵ou can easily imagine clinics trying to boost their revenue by offering this,鈥� says Lovell-Badge, who points out that unregulated clinics offering unproven stem-cell treatments are springing up all over the world.
Such irresponsible behaviour might be disastrous for the health of children 鈥� and the purses of their parents 鈥� but for now it poses no wider issues. We don鈥檛 know how to create superhumans even if we wanted to (see 鈥�Will CRISPR gene-editing technology lead to designer babies?鈥�).
The biggest impact from CRISPR will come from the enormous range of genetically altered plants, animals, fungi and bacteria it will be used to create. The technique has already been used to create , hornless cattle for farmers and micropigs for pets.
So far fears about genetically engineered plants and animals 鈥� that they will harm our health or the environment, for instance 鈥� have proved largely unfounded, but with CRISPR making it much easier to tinker with genes the odds of things going wrong will be greater. It鈥檚 possible, for instance, that plants given traits such as drought resistance, salt tolerance or faster growth will start spreading and become invasive weeds. Then again, other human activities such as introducing exotic species have already created many invasive weeds and pests.
Another risk comes from something called 鈥�gene drives鈥�, which CRISPR is making both easier to create and more powerful. Normally a genetic variant in an organism has a 50 per cent chance of being inherited by offspring. But a gene drive can insert a copy of itself to the DNA inherited from the other parent. That guarantees it gets passed to all of the organism鈥檚 offspring, meaning it can spread very rapidly through a population. In theory gene drives could be deliberately unleashed to wipe out unwanted species such as disease-carrying mosquitoes. But there are fears they could also spread uncontrollably in the wild as a result of lab accidents.
鈥淭here are fears that gene drives could spread in the wild as a result of lab accidents鈥�
鈥淲e need to be careful,鈥� says Austin Burt of Imperial College London, who works on gene drives. But the risk needs to be kept in perspective: we are already causing a sixth mass extinction because our activities are wiping out so many species. Gene drives would affect only one species at a time, and in species that reproduce slowly 鈥� like us 鈥� they would spread extremely slowly.
The worst-case scenario is that CRISPR is accidentally or deliberately used to engineer a pathogen that infects people or crops 鈥� a biological weapon, in other words. But it is already possible to do this in other ways.
The power of CRISPR means it could have huge benefits, allowing us to produce more and healthier food even as the climate changes, and to improve the health and welfare of ourselves, our pets and farm animals. But much depends on this power being used wisely. Or as the uncle of a fictional transgenic creation says: with great power comes great responsibility.
Read more: 鈥�CRISPR: The gene-editing revolution on our doorstep鈥�
(Image: Luis D茫颅az Devesa/Getty)
This article appeared in print under the headline 鈥淪hould we be worried?鈥�
