A group of researchers shocked the world in April when they revealed that they had used a revolutionary gene editing tool discovered in 2012 called CRISPR to edit the DNA of human embryos.
They used a tool that’s so simple, a person with molecular biology skills and know-how could probably do it in a bio-hacker space for less than $US2,000, according to experts.
And in fact, CRISPR — which can be used to modify genes in any cell — is so powerful and easy to use that some scientists think experimentation on human embryos was inevitable.
“As anticipated, because this sort of study is technically possible, it was going to be done,” Matthew Porteus, an associate professor of pediatrics in the division of stem cell transplantation told the Genetic Expert News Service.
The embryos used by the researchers were never going to develop into a person, but scientists are concerned about the future implications and effects of haphazard experimentation with human embryos. After all, it doesn’t require a massive, highly-regulated research university to use this powerful tool.
Jennifer Doudna, one of the co-discoverers of CRISPR, told MIT Tech Review‘s Antonio Regalado just how easy it was to work with the tool: “Any scientist with molecular biology skills and knowledge of how to work with [embryos] is going to be able to do this.”
Harvard geneticist George Church, whose lab is doing some of the premier research on CRISPR, says: “You could conceivably set up a CRISPR lab for $US2000.”
That’s cheap enough if someone wanted to edit human embryos, even if were illegal to do so, they could go ahead and do it (provided a molecular biologist was involved). Embryo modification is far from the only use of CRISPR, and not what most labs have any interest in doing with the tool, but in theory, that’s possible.
Using CRISPR to genetically engineer the DNA of an embryo is just like using it to work with any other bundle of cells, according to Oliver Medvedik, a professor and assistant director of a biomedical engineering center at Cooper Union and the co-founder of Genspace, a nonprofit community biolab where non-professional scientists can experiment with biotech.
It’s done using lab supplies you would find in pretty much any molecular biology lab — things that DIYBIO labs build themselves, according to Church, who is an advisory board member at Genspace.
The hardest part of doing CRISPR on human embryos (instead of other cells) would be getting the embryos themselves — that would require donated embryos or the resources of a fertility clinic, including a minor surgery for egg extraction.
Actually implanting and developing an embryo from there (something still in the future, since accurate embryo modification is still not possible) would be even more expensive — a typical IVF procedure costs $US12,000. But the genetic modification component itself? Easy and cheap.
How to modify genes — and embryos
CRISPR is essentially a package of molecules that can find specific sections of genetic code (patterns of the As, Ts, Gs, and Cs that form our blueprint) and snip off specific sections. Even more impressively, CRISPR can actually replace them with a new specific section of DNA.
In humans, this could be used for a variety of purposes. It could be used to target the segments of DNA that allow a virus to target cells, preventing a virus like HIV from doing its work. It could also theoretically allow scientists to edit or switch out the genes in an embryo that cause diseases like cystic fibrosis or the genes that code for a potentially serious blood disorder (which is what the research team in China was trying to do).
In theory of course, genetic editing could also be used to program specific “desired” genes into an embryo. If this embryo was implanted in a womb and brought to term, the person could pass their edited genes on to the next generation.
All a scientist has to do to make it work is inject the right set of CRISPR molecules that they want into a cell — in this case, an embryo — and the delivery system seeks out the sections you are looking for.
As Medvedik explains, once you have the equipment, you don’t need much more to work with CRISPR.
To replace a gene in a cell, you would first pick out the specific CRISPR molecules needed. Once you’ve figured out which to use, they can be ordered from Addgene.org or many other websites, and the RNA that guides them to the correct spot on a genome can then be synthesized.
The next step would be to deliver one CRISPR-associated molecule that would nick or cut the section of DNA you want to remove and then, if you want, have another CRISPR molecule start a repair process there that would replace the removed code with whatever you desire.
Medvedik says that no one has worked with CRISPR yet at Genspace, but that they certainly could (though it wouldn’t be to work with human embryos) — that CRISPR is just as easy to use as any other tool that edits DNA, except it’s much more efficient.
If you were trying to edit embryos that were going to develop, you’d want to check that they were successfully edited after injecting the CRISPR molecules. That includes isolating several cells from the clump that is the embryo, and sequencing their DNA to see that it shows the desired changes — and no others.
If you find you’ve successfully edited a human embryo, the only step stopping you from having your very own designer baby is to implant that embryo into a human woman.
Designer babies aren’t coming — yet — though
Medvedik knows that the embryo experiment got a lot of attention, but “the real technological breakthrough,” he explains, was the discovery of CRISPR in 2012.
“Using it to knock something out in a human embryo,” like the researchers who generated all the stir recently did, “is no different than using it knock out something in a monkey cell,” he explains, which is research that has already been done.
But for now, the controversial CRISPR experiment showed us that this method is still far too inaccurate to actually be used for something like that (ethical questions aside).
The Sun Yat-sen University group tried to edit the DNA of 86 embryos (all nonviable). Of the 71 that survived the process, they examined 54, and CRISPR had only successfully made cuts in 28. Only a “fraction” of those actually had new DNA added to their genetic code. The CRISPR system also made additional, unintended cuts and substitutions, which could create new diseases. In other cases, it made the right changes in some cells of the embryo but not all of them, which could cause other problems.
Church told Business Insider that there are already much more accurate versions of CRISPR than the molecules chosen in that research, so there’s already a possibility that current techniques may be better than those used in the study.
It’s a fast-changing technology that has only been around a couple of years, but researchers are expected to publish more than 1,100 papers detailing their research on CRISPR this year alone, and much of that research involves making the system more efficient and accurate.
Improved accuracy means we could start to see CRISPR treatments that could wipe out the infectious potential of viruses like HIV — and eventually we could get to the point that it’s possible to edit human embryos without creating all kinds of mutations.
Scientists like Doudna want us to take time to consider what it means to change the DNA people pass on before we go ahead and do it. But with this technology being this easily accessible and these experiments being technologically feasible, it’s hard to think that somewhere, it won’t happen.
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