Science Friday Your DNA is constantly mutating, and that’s a good thing
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Apr 27, 2026 
Roxanne Khamsi, science writer and author of Beyond Inheritance, explores how our DNA is constantly changing and why that matters. She discusses mutation origins, the mosaic nature of our bodies, how mutations shape immunity and aging, and surprising cases where mutations can correct disease. The conversation also covers cancer diversity, single-cell sequencing, and limits of anti-aging hopes.
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Mutation Is Necessary For Immune Defense
- Mutation is essential for adaptive immune function because immune cells deliberately rearrange DNA to create diverse antibodies.
- Khamsi explains people with hyper-IgM syndrome can't mutate immune cells effectively and suffer severe infection risk.
Understand Vaccines Drive Beneficial Immune Mutations
- Accept that vaccines induce mutation-like DNA rearrangements in immune cells to produce antibodies; this is a normal, protective process.
- Khamsi compares infection and vaccination as both prompting immune cell DNA rearrangement to find effective antibodies faster.
Cancers Contain High Intratumor Genetic Diversity
- Tumors are genetically diverse hotbeds rather than the result of only one or two mutations, complicating treatment resistance.
- Khamsi mentions colorectal cancers may undergo an early 'big bang' of mutations that seed high intratumor diversity.
