Radiolab – "Antibodies Part 1: CRISPR" (June 6, 2015)

Episode Overview

This episode dives into the revolutionary genetic technology known as CRISPR, tracing its discovery, biological function, and the profound ethical and societal questions it raises. Hosts Jad Abumrad and Robert Krulwich explore the origins of CRISPR, its role as a microbial immune system, and its explosive potential as a cheap, precise, and universal gene-editing tool. Through conversations with science writer Carl Zimmer, biochemist Jennifer Doudna, and other researchers, the episode weaves scientific insight with the excitement, hope, and anxiety surrounding the technology's rapidly expanding capabilities.

Key Discussion Points & Insights

1. Discovery of CRISPR: A Scientific Mystery

• Conference Party Anecdote
  Jad Abumrad recounts an encounter with excited biologists at a conference:

  “They started to lose their shit, like, genuinely lose their shit about this thing called CRISPR.” (01:56)

• CRISPR first observed in a 1987 Japanese paper as a strange repeated DNA pattern in E. coli (03:02)
• Over time, these sequences were found in many bacteria, suggesting unknown but important biological function.

2. Biology of CRISPR: Bacteria's Immune System

• The strange DNA: repetitive sequences with unique “blurps” between them.
• Scientists discover “blurps” are snippets of viral DNA:

  "All these bacteria have little snippets of virus DNA wedged in these particular places in their genome, which is a little weird if you think about it." – Carl Zimmer (06:23)

• Eugene Koonin proposes these are virus “mugshots”—basically a bacterial memory of invaders, akin to a most-wanted poster (08:13)
• Mechanism: When attacked by a familiar virus, bacteria use CRISPR to recognize and immediately destroy invaders using “molecular assassins”:

  “Take this mugshot. If you see anything that matches this pattern, kill it.” – Carl Zimmer (11:15)

3. CRISPR as a Powerful Genetic Tool

• Jennifer Doudna and others realize CRISPR could be repurposed for targeted genome editing:

  “This could be an amazing technology... This is a tool we can use to cut DNA where we want to cut DNA.” – Jennifer Doudna (12:50, 12:57)

• Implications: Targeting any gene (e.g., those causing diseases like hemophilia), “smart scissors” can precisely cut and potentially replace genetic material (13:48)
• Repair is easier than expected — new genetic material can be “thrown” in the vicinity, and repair enzymes install it (14:03).
• Cheap and precise compared to older techniques ($75 vs. $5,000 per experiment) (16:13)
• Works in virtually any organism:

  “I'm waiting for someone to say CRISPR doesn't work in species X and I have not heard of that.” – Carl Zimmer (16:39)

4. The Post-CRISPR World: Possibilities and Perils

• Beyond curing disease, CRISPR can be used for “semi-science-fiction”:
  • Resurrecting extinct creatures (e.g., making a chicken into a dinosaur-like creature, or bringing back woolly mammoths) (21:57)
  • “Designer” traits in humans (e.g., taller children, stronger muscles) (22:37)
• Raises a profound philosophical/ethical debate:

  "There's something about human beings, including scientist human beings... there's an angelic side ... and there's a very, very difficult side. As the human beings get more and more power... that future will include the imaginations, both light and dark, of humans." – Robert Krulwich (24:54)

5. Ethics, Limits, and the Start of a New Era

• Jennifer Doudna and others underline the red line: no use on human sperm/egg cells or embryos (27:18)
• Editing embryos = permanent, heritable changes; consent is impossible (27:26)

  "If you imagine making these changes and they cascade through generation after generation... it's kind of profound." – Jennifer Doudna (27:41)

• Line is quickly crossed: Chinese researchers announce editing of human embryos with CRISPR (28:01)
• Results not perfect: success only in 28/86 embryos, with errors present (30:37)
• Stresses that while not ready for use in humans, the technology is advancing fast and could soon be “guaranteed safe” (30:55)
• Societal acceptance likely, given precedent with IVF and gene selection (32:07)
• Irresistible logic of genetic upgrades, e.g., for disease resistance:

  "If you'd like, for an extra thousand dollars, we will... use CRISPR to give them the Alzheimer protecting variant. Would you like that?" – Carl Zimmer (32:26)

• Hosts acknowledge “we've already answered the question” about whether humanity will use this tool (33:41)

Notable Quotes & Memorable Moments

• CRISPR’s Name and Branding:

  “It’s like a furniture manufacturer or something.” – Jad Abumrad (04:58)

• Mechanism Metaphor:

  "It's like little Polaroid shots of the enemy." – Robert Krulwich (08:08) “Imagine Pac man, but kind of misshapen and rough.” – Jennifer Doudna (11:25)

• First Use in Human Embryos (China):

  "It's a way of hacking evolution itself." – Alex Honl (28:09)

• The Unstoppable Progression:

  "Who's going to say no to that?" – Jad Abumrad (33:41)

• Cultural & Ethical Reflections:

  "I think we should cringe a little as opposed to just having a big party." – Robert Krulwich (26:18)

Timestamps for Major Segments

• Main story begins/party anecdote — 01:23
• CRISPR’s bacterial origin & function — 03:04 to 14:44
• CRISPR as a tool, advantages over old methods — 15:02–17:30
• Speculative uses: de-extincting species, designer babies — 21:41–23:41
• Ethical debate: Should we do this? — 24:38–27:47
• Crossing ethical lines: First human embryo edits in China — 27:55–30:47
• Comparisons to IVF and likely future acceptance — 32:07–33:46

Conclusion

Radiolab’s “Antibodies Part 1: CRISPR” navigates from the roots of CRISPR as a microbial “memory” system to its sudden arrival as the world’s most potent, accessible, and controversial gene editing tool. With playful banter, vivid metaphors, and growing unease, the episode foreshadows the profound choices and challenges humanity now faces—from curing diseases and resurrecting mammoths, to editing human destiny itself. The conversation closes on a sober recognition: the future of CRISPR is not just a scientific question, but an ethical and societal test already underway.