Nancy Gibbs

I'm sentimental about many things: the lumpy feel of a baby's unused feet, the metallic smell of the air before the first snow, the last scene in 'It's a Wonderful Life.' But Valentine's Day leaves me cold.

What do cells do when they see a broken piece of DNA? Cells don't like such breaks. They'll do pretty much anything they can to fix things up. If a chromosome is broken, the cells will repair the break using an intact chromosome.