The world is waking up to CRISPR. American media giant CBS sets out to explain to the public what genome editing is – and why it matters – by interviewing some of the top scientists behind the technology in a recent episode of 60 Minutes.
Professor Feng Zhang, of MIT and the Broad Institute, tells CBS correspondent Bill Whittaker: 'There are about 6000 or more diseases that are caused by faulty genes. The hope is that we will be able to address most, if not all of them'.
Professor Zhang's colleague, Professor Eric Lander, spoke about his experience on the Human Genome Project. 'We could read out all the human DNA, and then, in the years afterwards, find the misspellings that caused human diseases. But we had no way to think about how to fix 'em. And then, pretty much on schedule, this mind-blowing discovery that bacteria have a way to fix those misspellings, appears.'
I was surprised to learn the speed and scale at which the technology is being adopted. Professor Zhang says it is being used in 2200 labs, in 61 countries. At the University of California, scientists used CRISPR to edit mosquitoes so they can't transmit malaria. Their colleagues are modifying rice to withstand extreme weather. In China, scientists created very muscular beagles (as reported by BioNews 825). And, of course, there are the medical implications.
The programme quickly moves on to focus on this promising area, in particular the work of Professor Kang Zhang – an ophthalmologist and professor at the University of California, San Diego. He used genome editing in mice with retinitis pigmentosa, a genetic form of blindness. His team injected CRISPR into the eyes of blind mice to deactivate the main disease gene. It took three months to see the results – the mice recovered 30 to 50 percent of their vision. Now Professor Kang Zhang is trialling the same approach on monkeys in China, and results are promising so far.
All this could mean 'big bucks', as CBS puts it. Indeed, CRISPR is projected to be a multi-billion dollar market within a decade.
Right now the Broad Institute and Professor Feng Zhang hold a primary patent for CRISPR's use in human cells in the USA. But CBS explain that they are being challenged in court by the University of California, Berkeley where Professor Jennifer Doudna and Professor Emmanuelle Charpentier of the Max Planck Institute for Infection Biology, Germany, made landmark discoveries predating Professor Zhang's work.
I had wondered why Professors Doudna and Charpentier had not been interviewed for this programme – this court case may be the reason why.
Finally, the show moves on to talk about the most controversial aspect of genome editing: germline editing. This could be used to produce a disease-free utopia or a eugenic dystopia depending on your point of view. Human germline editing has been outright banned in many countries, which CBS does not emphasise clearly enough.
CBS interviews Professor Shoukhrat Mitalipov, whom the show describes as 'a maverick'. He runs the Centre for Embryonic Cell and Gene Therapy at Oregon Health and Science University.
Professor Mitalipov led an international team of scientists who used CRISPR on human embryos to correct a single gene mutation that causes a fatal heart disease called hypertropic cardiomyopathy. They demonstrate eggs being fertilised with edited sperm. The result? Instead of 50 percent being free of the fatal mutation, now 72 percent are (these eggs are never implanted).
The programme does not point out that there is already a fully effective and legal way to prevent a heritable mutation being passed down – embryo selection (not to mention, of course, family-building choices like adoption).
The over-dramatisation reaches its peak as Bill Whitaker tells Professor Mitalipov: 'Your critics say that you're playing God.' He replies: 'God gave us brains so we could find a way to eliminate suffering of human beings. And if that's, you know, playing God, I guess that's the way it is.'
Professor Mitalipov wants to use genome editing to stop genetic diseases, but the concern is his research has paved the way for others to create so-called designer babies. However, ultimately the interviewees agree that the technology is not ready to genetically edit the human germline, for disease or other reasons.
But CRISPR is gearing up to edit human somatic (body) cells to help cure diseases. The programme ends by mentioning that a small clinical trial, the first in the USA using CRISPR to target cancers, is now enrolling patients.
The CBS episode did contain some fascinating facts, explained with accessible language, but I cannot condone its neglect of Professor Doudna and her colleagues. Without them, CBS is only telling half the story of CRISPR. For readers as disappointed as I was, Vox does a better job in its episode 'Designer DNA' in its Netflix series, Explained.