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 genes changed, showing how the human body adapts to its environment.

Read more from the NASA study: https://www.nasa.gov/feature/nasa-twins-study-confirms-preliminary-findings

CORRECTION: A previous version of this story said the brothers were no longer identical. NASA has since issued a clarification saying, "Mark and Scott Kelly are still identical twins; Scott's DNA did not fundamentally change. What researchers did observe are changes in gene expression, which is how your body reacts to your environment."