NASA says twin astronauts DNA now different after space travel

NEW YORK -- You would expect a trip to space to be transformative, but NASA says it can lead to permanent DNA changes.

The space agency studied the DNA of twin astronauts Scott and Mark Kelly.

Scott spent a year on the International Space Station while Mark remained on Earth.

Now two years later, NASA says 7 percent of Scott's DNA has changed, meaning the brothers are no longer identical.

Read more from the NASA study