Astronaut Who Spent Year In Space No Longer Has Matching DNA To Twin

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An astronaut who spent a year in outer space no longer has matching DNA to his identical twin brother, the New York Post reported Wednesday.

Scott Kelly, an astronaut who broke the record for the most consecutive days spent in space, has changes in his gene expression that his identical twin brother Mark Kelly, also an astronaut, does not have, according to the report. The findings are based on NASA’s “Twin Study.”

Researchers found changes based on how genes express themselves under stress, reported. Seven percent of Kelly’s gene expression experienced changes that did not return to preflight expression after six months back on Earth, based on results published Jan. 31.

Researchers found that Kelly’s 340 days in orbit caused the changes. “Researchers now know that 93% of Scott’s genes returned to normal after landing,” NASA reported. “However, the remaining 7% point to possible longer term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia.”

“This could be good news! I no longer have to call @ShuttleCDRKelly my identical twin brother anymore,” joked Scott Kelly in a tweet about a Newsweek article.

“I used to have an identical twin brother. Then this happened…,” Mark Kelly also tweeted about a CNN article.

The Weekly Standard noted that other news sites sensationalized information about NASA’s findings after outlets claimed the twins no longer have the same genetic coding. Kelly still has the same DNA, yet now has changes to the way some of his genes are expressed. NASA says the change is “very minimal.”

“Mark and Scott Kelly are still identical twins; Scott’s DNA did not fundamentally change,” NASA stated on Thursday. “What researchers did observe are changes in gene expression, which is how your body reacts to your environment. This likely is within the range for humans under stress, such as mountain climbing or SCUBA diving.”

Mark Kelly is the husband of former Democratic congresswoman Gabrielle Giffords of Arizona who survived an assassination attempt in 2011 after getting shot in the head. She resigned from Congress in 2012.

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