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DNA Repair

October 18, 2005

People get skin cancer from sitting out in the sun all day. So why don’t plants?


Protection from DNA damage. I’m Bob Hirshon and this is Science Update.

Recently we answered a listener’s question about how plants protect themselves from the sun’s ultraviolet light. We learned that colorful pigments act like sunscreen, neutralizing UV rays.

But the story doesn’t end there: Some UV light can sneak through and damage the plant’s DNA. In this case, says biophysicist Dongping Zhong of Ohio State University, the plants call on an enzyme called photolyase. The photolyase uses energy from the sun’s visible light to inject an electron into the site of the damage. That jostles the atoms in the DNA back to their original places.

DONTPING ZHONG (Ohio State University):
They automatically will fix it.

Most animals also have photolyase, but mammals don’t, which leaves us open to skin cancer. Zhong hopes his research will point to new treatments.

I’m Bob Hirshon, for AAAS, the science society.