Hosted by Lester Nare and Krishna Choudhary, this single-story deep dive tells the full story of how humanity uncovered the structure of DNA — and the human tensions that shaped it. From Mendel’s pea-plant mathematics to Rosalind Franklin’s groundbreaking x-ray crystallography, from Cavendish–King’s College rivalries to the famous Photo 51, this episode follows the scientific and ethical arc behind one of the most important discoveries in modern biology.

Summary

• Before DNA — Mendel’s inheritance laws, Miescher’s nuclein, Levene’s early models, and why scientists initially believed proteins carried heredity.
• The turning point — Griffith’s transformation experiment and the Avery–MacLeod–McCarty proof that DNA is the genetic material.
• The physics connection — Schrödinger’s What Is Life? and the idea of an “aperiodic crystal” inspiring Watson, Crick, and a generation of physicists to enter biology.
• Two labs, one race — Cavendish vs. King’s College, Wilkins vs. Franklin, and the clash of personalities, methods, and interpretations.
• Photo 51 — Franklin and Gosling’s pivotal diffraction image revealing the helical structure of DNA.
• The model — base pairing, antiparallel strands, and why the double helix immediately explained replication.
• Recognition & legacy — the 1953 Nature papers, the 1962 Nobel Prize, Franklin’s omission, and Watson’s later controversies reshaping his legacy.

Show Notes

• Mendel (1866) — Pea Plant Genetics
• Griffith (1928) — Transformation
• Avery–MacLeod–McCarty (1944)
• Schrödinger — What Is Life?
• Franklin’s Photo 51
• Watson & Crick (1953)