Quirks & Quarks

Nature vs. nurture: lessons from twins

NASA's twin study can teach us a lot about the human mind and body.
Astronaut Scott Kelly and his identical twin, Mark, also a former astronaut, are the impetus behind a massive study on the effect of long duration travel in space. (NASA)

NASA astronaut Scott Kelly returned to Earth in March, 2016,  after spending almost a year on the International Space Station. 

 Scott has an identical twin, Mark, who was also an astronaut until he retired in 2011. 

The brothers' almost identical genome is giving researchers a unique chance to do a "nature versus nurture" study. Mark was the control down here on Earth, while Scott was in space.  Researchers took samples on both brothers before, during and after Scott's time in space. 

The research is helping NASA understand how the body might stand up to the stresses of extended time in zero-gravity. Ultimately, it might tell them what they need to know about a round trip to Mars. 

There are 10 research groups looking at different aspects of the human body in space. Bob McDonald spoke with Dr. Susan Bailey, who's leading the telomeres study. It looks at astronaut's chromosomes to find out how space affects stress-related aging.

Blair and Elysse Elliott of London, Ontario pose for a photo August 3, 2002 at the Twins Days Festival in Twinsburg, Ohio. (Mike Simmons/Getty Images)

Twin studies have played an important role in allowing scientists to determine how much of our nature comes from our genes versus our environment. 

Dr. Nancy Segal is a professor of Psychology and the Director of the Twin Studies Centre at California State University in Fullerton. She's also the author of many books on twins, including "Born Together, Reared Apart," about a landmark study she worked on with twins raised apart and a new book soon to be released called, "Twin Mythconceptions: False Beliefs, Fables, and Facts about Twins."

She says most behaviours have been looked at in twin studies, and that scientists have been able to figure out how much of a role genetics plays in a person's intelligence, personality, and even temperament. When it comes to twins who were raised apart, Dr. Segal says they give scientists an even more unique ability to determine "a pure estimate of the genetic effect."