StarTalk Radio
Episode: "Building Life from Scratch with Kerstin Göpfrich"
Host: Neil deGrasse Tyson
Co-host: Matt Kirshen
Guest: Prof. Dr. Kerstin Göpfrich, Center for Molecular Biology, Heidelberg University
Release Date: September 2, 2025

Episode Overview

This StarTalk episode takes listeners into the cutting-edge world of bottom-up synthetic biology: the science of building novel forms of life from the most basic components. Astrophysicist Neil deGrasse Tyson and comedian Matt Kirshen sit down with Professor Kerstin Göpfrich, biophysicist and leader of the Max Planck Research Group at Heidelberg University, to explore what it means to create life in the lab, what definitions of "life" scientists work with, and how this emerging field could revolutionize both our understanding of biology and future technologies.

Their lively conversation covers not just the nuts and bolts of building synthetic cells, but also the philosophical, ethical, and practical implications of “playing God” in the laboratory, what counts as alien life, and where this research could lead scientific advancement and humanity itself.

Key Discussion Points and Insights

1. What Does It Mean to Build Life from Scratch?

• Defining Life (06:01):

  • Scientists haven't reached consensus, but synthetic biologists work with the NASA definition:
    "A self-sustaining chemical system capable of Darwinian evolution."
    -- Prof. Göpfrich (06:15)
  • They aim for "open-ended evolution," meaning systems that can increase in complexity and evolve new functions, not just survive.

• Darwinian vs. Open-ended Evolution (07:01):

  • Darwinian evolution involves survival-based changes; open-ended evolution offers a broader exploration of possible forms and new properties.
  • Prof. Göpfrich emphasizes the importance of mortality for evolution:
    "Introducing death into living systems is absolutely crucial... otherwise, you just have exponential growth and the resources will be exploited."
    -- (08:10)

2. Bridging Chemistry and Biology: Historical Context (09:44)

• The Miller-Urey Experiment:
  • Simulated the early Earth environment to show that simple life building blocks, like amino acids, can arise from non-living chemistry (10:12).
  • Göpfrich draws a parallel between early chemists disproving that only life can synthesize organics, and today’s goal to transition from matter to life in the lab (11:58).

3. The Bottom-up Approach: How to Construct Life

• Starting with Biomolecules (13:07):

  • Göpfrich’s group assembles cell envelopes (lipid vesicles) and builds molecular machinery from RNA, inspired by theories of the “RNA World” (13:57).
  • Instead of mechanical tools, they use computationally designed DNA to code RNAs that fold into functional nanostructures (15:49).
  • "We are trying to assemble a synthetic gene from scratch... DNA which encodes an RNA that folds up into a desired structure while transcribed."
    -- Prof. Göpfrich (15:04)

• RNA Origami:

  • Designing RNA to fold into structures that mimic cytoskeletal components or pores, enabling basic cell-like functions.

• Design Iteration (22:15):

  • Start with computational design, then build and test structures via cryo-EM, tweaking DNA as needed.

4. Creating "Alien" Life—How Different Could Synthesized Life Be?

• Synthetic Life vs. Re-creating Known Life (22:41):

  • Göpfrich describes approaches ranging from encapsulating cellular proteins to creating wholly novel systems.
  • She explains the massive complexity of natural cells—just translating RNA into protein needs 150 genes—and their aim is to simplify: "If we can circumvent the use of proteins... and just build a functional machinery from RNA... then we can reduce the complexity of the system quite a lot."
    -- Prof. Göpfrich (24:02)

• Implications for Astrobiology (26:27):

  • Tyson probes if life elsewhere would use the same DNA-RNA-protein machinery.
  • Göpfrich doubts inevitability:
    "The evolutionary landscape is vast. With life as we know it, we are just exploring a tiny, tiny, tiny, tiny, tiny bit of that."
    -- (27:20)
  • By creating minimal synthetic cells, scientists may discover alternative metabolisms, offering insight into how life could differ across the universe.

• Carbon vs. Silicon Life:

  • Carbon's chemical versatility and abundance make it the clear winner, but exploring alternatives is a frontier for both synthetic biologists and astrobiologists (28:22).

• Convergent Evolution:

  • Tyson and Kirshen highlight how evolution often "finds the same solutions" via unrelated routes—suggesting certain forms are optimal for survival (30:12).

5. Deep Dives: Molecular Handedness and the Limits of Biology

• Molecular Chirality (32:26):

  • All known life uses left-handed amino acids (homochirality).
  • Tyson wonders if right-handed life could exist undiscovered; Göpfrich says no traces have been found.
    "Make me believe very strongly... that the left-handed version is the one that made it."
    -- Prof. Göpfrich (36:32)

• Ethics of Creating Life (40:09):

  • Are we risking dangerous life forms, or "overlords"? Göpfrich reassures: "What we are creating is very, very fragile and requires a lot of care... Ethics is, of course, extremely important."
    -- (40:49)
  • She calls for extending biosafety and containment rules, even for synthetic life forms (41:41).

6. Motivations and Practical Applications (43:02)

• Why Do It? Human Curiosity and Practical Uses
  • Göpfrich: "I'm just super, super curious about what life is and what it could be." (43:02)
  • Building synthetic cells could provide revolutionary manufacturing tools, including advanced therapeutics, vaccine delivery, evolvable materials, and deeper insight into both evolution and medicine (44:05).
  • RNA origami techniques allow more stable and compact therapeutics, with impacts for real-world health (46:05).

Notable Quotes and Memorable Moments

• On evolution and death:
  "You're the first biologist I've heard be honest about the fact that Darwinian evolution requires that everybody dies."
  — Neil deGrasse Tyson (08:38)

• On ambitions of synthetic biology:
  "In the end it would be amazing to have not just biology 2.0, but also 3.0, 4.0, 5.0 and so on."
  — Prof. Göpfrich (25:22)

• On molecular design:
  "We are trying to assemble a synthetic gene from scratch, a piece of DNA which encodes for an RNA that folds up during transcription... into a desired structure."
  — Prof. Göpfrich (15:04)

• On the vastness of possible biochemistries:
  "The evolutionary landscape is vast. With life as we know it, we are just exploring a tiny, tiny, tiny, tiny, tiny bit of that."
  — Prof. Göpfrich (27:20)

• Philosophy and playfulness:
  "Tell your parents that, too, in case they were wondering."
  — Neil deGrasse Tyson to Matt Kirshen, on being “a part of civilization” (02:32)

• On motivations:
  "It's somehow intrinsic to human curiosity to ask what life is and why it's there and so on. And recreating it, building it is one way to really bring our understanding of life to a new level."
  — Prof. Göpfrich (43:02)

Timestamps for Important Segments

• [06:01] — Working Definition of Life and Open-Ended Evolution
• [09:44] — Miller-Urey Experiment and Historical Context
• [13:07] — Lab Methods: Lipid Vesicles, RNA Nanotechnology
• [15:04] — RNA Origami: Designing and Building Synthetic Genes
• [22:41] — Natural vs. Synthetic Life; Simplifying Complexity
• [26:27] — Life in the Universe: Would Aliens Use the Same Machinery?
• [32:26] — Chirality: Why All Life is Left-Handed
• [40:09] — Ethics and Containment: Should We Worry?
• [43:02] — Motivation: Curiosity, Technology, and the Promise of Evolvable Tools
• [46:05] — Practical Applications: Stable RNA Therapeutics

Tone and Language

The conversation is both playful and intellectually rich, brimming with curiosity and humor. Tyson and Kirshen keep the mood light with jokes about playing God and “illegal aliens”—while Göpfrich stays grounded, pragmatic, and infectiously enthusiastic about the possibilities of her research.

Conclusion

This episode offers a lively, accessible, and deeply informative journey through the frontiers of synthetic biology. The insights into how scientists define life, the nuts and bolts of building it from scratch, the ethical and philosophical quandaries, and the tantalizing implications for medicine, astrobiology, and the future of life itself, make this a must-listen for anyone intrigued by humanity’s quest to understand (and perhaps reinvent) life as we know it.