How Did Life Begin? with Betül Kaçar

May 5, 2026

AI Summary

5 min read

How Did Life Begin? with Betül Kaçar

The first two billion years of life on Earth left almost no trace. Rocks erode, fossils are rare, and microbes—the dominant life form for most of planetary history—don't leave bones. Astrobiologist Betül Kaçar, a professor of bacteriology at the University of Wisconsin-Madison, has found a way around this problem: instead of searching for ancient fossils, she resurrects ancient enzymes by reconstructing their DNA sequences and inserting them into living microbes, forcing the bacteria to "speak an ancient dialect." Her lab's recent paper in Nature used this technique on a nitrogen-fixing enzyme, and the work has implications not just for understanding life's deep past, but for agriculture, planetary science, and how we search for life beyond Earth.

Resurrecting Extinct Proteins

Kaçar's approach begins with a fundamental problem: life constantly overwrites itself. "If I walk in the snow, you can tell my footsteps for some time, and then snow melts and my marks are gone," she explains. The same is true for microbial life—its traces are erased over billions of years. Geologists have rocks that sit unchanged for hundreds of millions of years; biologists have no such archive.

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What you'll learn

1 (04:47) **Introducing Betül Kaçar and Her Research** - Neil and Chuck welcome Betül Kaçar, director of a NASA-funded center and professor of bacteriology at UW-Madison.
2 (07:02) **Resurrecting Ancient Enzymes: The “Jurassic Park” of Biology** - Kaçar describes the Nature paper and the technique of bringing extinct proteins back to life.
3 (11:17) **How the Resurrection Works: From DNA to Function** - Neil and Kaçar detail the step-by-step process of reconstructing ancestral enzymes.
4 (14:20) **The Singularity Problem: Why Only One Genesis of Life?** - Neil asks why all life on Earth shares DNA if life was so easy to start.
5 (16:48) **Nitrogen Fixation Explained: The Engine Behind Life** - Kaçar breaks down what nitrogen fixation is and why it’s a critical singularity.
6 (22:44) **Why Resurrecting Ancient Enzymes Matters for Our Future** - Kaçar connects her astrobiology work to practical applications.
7 (27:00) **Planetary Microbiology: A New Paradigm** - Kaçar introduces the concept of studying microbes from the perspective of the planet.

+ Full timestamped outline available in the app

Show Notes

What are the true limits of life, will we even recognize it when we see it? Neil deGrasse Tyson and comic co-host Chuck Nice explore the beginnings of life on Earth and what they might tell us about life everywhere else with astrobiologist and bacteriologist, Betül Kaçar.

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