Hi, this is Ira Flato, and you're listening to Science Friday. Right now, your DNA is mutating. Yes, yours. Well, and mine too. And no, I'm not giving you an early cancer diagnosis. Cancer and mutations obviously go hand in hand, but you may be surprised to know that

our bodily systems are rife with mutations. These errors and attempts to repair them are a key to

understanding immune function, aging, and even how heart disease develops. In fact, gene mutations can even mitigate the harm

caused by some inherited diseases. My next guest is here to take us on a journey through the

illuminating science of genetic mutations. Roxanne Camsey is a science writer and author of the

new book, Beyond Inheritance, are ever-mutating cells and a new understanding of health.

She's based in Montreal, Quebec. Welcome to Science Writer. Welcome back. Thank you so much, Iris.

Great to be back. Nice to have you. Okay, you know, most of us think about our DNA as it's static,

it's stable, kind of like a personal ID number. How should we be thinking about

how our DNA changes over the course of our lives? So I was taught the same thing. I was taught

that the DNA inherited from my mother and my father is the same in all of my cells. And

what I discovered about eight years ago was that's not the

whole picture and that scientists right now are uncovering that each human body is a landscape

of genetic diversity and that our DNA is dynamic. It's not static. In fact, scientists estimate

that if a person reaches 100 years old, a single white blood cell will have around 3,000 mutations that are not found in the rest of their body.

So this is the new understanding of genetics I really feel is important that our DNA changes over time.

Why are mutations so rampant then in our cells?

So part of this has to do with the fact that we are a collection of cells.

We all start as a single cell for the first 24 hours after we're conceived.

And then by the time we reach adulthood, we're around 30 to 40 trillion cells. And that's not

counting the 30 trillion cells in our gut microbiome that are microbial cells. And there's a lot

of turnover to maintain this mass of cells that we are. Every time a cell divides, it's trying to

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