Radiolab, 24 February 2017
Part One presented by Jad Abumrad and Robert Krulwich
Part Two presented by Molly Webster and Soren Wheeler
Part One of the podcast was originally broadcast in 2015, but the producers have now re-released it along with Part Two – an update on the crazy last two years, which have seen CRISPR on the science pages, and sometimes the front pages, of newspapers.
Radiolab co-host Jad Abumrad starts Part One by describing a now-familiar scene at scientific conferences – a huddle of drunk biologists getting excited about the latest CRISPR news.
'I was standing there with some biologists and they started to lose their shit – like genuinely lose their shit – about this thing called CRISPR. I have never seen scientists as excited as this about anything,' he recounts. He contacted the veteran New York Times science writer Carl Zimmer to find out more.
The story begins in 1987 at the discovery of a strange stretch of repeating DNA in bacteria. We follow as scientists discover that CRISPR is the bacteria's defence system and then, finally and most importantly, when they realise that CRISPR can be used as a tool for editing all genomes. Radiolab tells the story in their typically flamboyant style, filled with interview clips and dramatic music. Though engaging, this highly edited style, with its constant cuts and sound effects, sometimes jars.
With the basics of CRISPR covered, the discussion then moves on to the possibilities of the technology, from resurrecting extinct species to treating diseases. This led to a slightly strange tangent on the ethics of designing 'winged pigs', a conversation quickly brought back on track by Zimmer. On the topic of using CRISPR in humans, the presenters had differing views. While Abumrad is positive about the possibilities, co-host Robert Krulwich expressed a more conservative viewpoint, asking us 'to cringe a little' and think more about the consequences of humans having access to this technology. 'Where does the sacred begin and end?' he asked.
This conversation came to a head when the hosts discussed the news of the first-ever genetic modification of human embryos using CRISPR (see BioNews 799). The technology, though successful, did not work efficiently and scientists concluded that it was not yet ready for application in the human germline.
'We are still in this fortunate position where we can say – it's dangerous so we shouldn't use it on human embryos. I just don't think we'll be able to find refuge there in ten or 20 years,' said Zimmer. This led on to the inevitable question, what will we do when CRISPR is ready?
There are concerns that using CRISPR on embryos could lead to 'designer babies' with genes for traits such as intelligence. Zimmer finished part one with the hypothetical situation of using CRISPR to engineer embryos with genes that protect against Alzheimer's (see BioNews 665). Abumrad replied: 'Who's going to say no to that?'
While this was an interesting conversation, I felt like we were led straight down the 'slippery slope' and into an extreme use of the technology. This was a missed opportunity to discuss the applications of CRISPR in basic research that may not always be presented to the general public – for example, the work of Dr Kathy Niakan to understand more about embryo development (see BioNews 837). Fortunately, the episode update that followed two years later provided an expanded view of the possible applications.
While the first episode felt a little slow for those already familiar with the subject, the updated second half jumped straight into some of the most interesting developments (including the CRISPR-based TV show starring Jennifer Lopez).
Part Two is presented by Molly Webster and Soren Wheeler, who discuss the CRISPR patent dispute (see BioNews 889), the treatment of mice with muscular dystrophy (see BioNews 834), the first steps in human clinical trials (see BioNews 878) and the potential of using CRISPR as an alternative to antibiotics. These topics were interesting, but were each given just a few minutes – not enough time for the in-depth discussion I would have liked.
The most controversial and far-reaching topic was the 'gene drive' system, which harnesses CRISPR to spread mutations through a population. Using a gene drive, scientists can ensure that all offspring of a mosquito will inherit an engineered malaria-resistant gene. If released in the wild, the malaria-resistant gene could spread rapidly within the mosquito populations, potentially wiping out the disease in some areas (see BioNews 830).
The research is impressive yet the potential ecological consequences if it goes wrong are, as Webster says, 'terrifying'. With gene drives, 'it is theoretically possible for one person to decide to change the local, or possibly global, environment', said Dr Kevin Esvelt of the Massachusetts Institute of Technology. The programme ended with the rather far-fetched idea of using gene drives in humans.
Overall, I would highly recommend this podcast, particularly for non-scientists who aren't familiar with CRISPR. Radiolab expertly traversed the complex world of genome editing and provided a thought-provoking introduction to CRISPR's potential. While there were points in the podcast that lacked depth and bordered on sensationalism, Radiolab are excellent storytellers who keep you listening to the last minute.