NASA Clears Up DNA Questions from Twins Study

"The change related to only 7 percent of the gene expression that changed during spaceflight that had not returned to preflight after six months on Earth. This change of gene expression is very minimal," NASA explained in a March 15 statement.

NASA issued a statement on March 15 that clears up some questions about the whether the DNA of astronaut Scott Kelly changed significantly during a year aboard the International Space Station. Because Scott has an identical twin, Mark, also an astronaut, who stayed on Earth during that year, NASA conducted the Twins Study and invited research teams to take part in finding out what the effects on the human body were from such a long time in space.

"Mark and Scott Kelly are still identical twins; Scott's DNA did not fundamentally change," NASA explained in the statement, saying what some interpreted as a 7 percent change in Scott's DNA was actually "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."

"The change related to only 7 percent of the gene expression that changed during spaceflight that had not returned to preflight after six months on Earth. This change of gene expression is very minimal," the agency explained. "We are at the beginning of our understanding of how spaceflight affects the molecular level of the human body. NASA and the other researchers collaborating on these studies expect to announce more comprehensive results on the twins studies this summer."

Most of the biological changes Scott experienced in space quickly returned to nearly his pre-flight status; a few persisted after six months, according to NASA, which explained:

"Scott's telomeres (endcaps of chromosomes that shorten as one ages) actually became significantly longer in space. While this finding was presented in 2017, the team verified this unexpected change with multiple assays and genomics testing. Additionally, a new finding is that the majority of those telomeres shortened within two days of Scott's return to Earth. Another interesting finding concerned what some call the 'space gene,' which was alluded to in 2017. Researchers now know that 93% of Scott's genes returned to normal after landing. 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 [excessive carbon dioxide in the bloodstream]. Increasing mission duration from the typical six-month ISS mission to one year resulted in no significant decreases in Scott’s cognitive performance while inflight and relative to his twin brother Mark on the ground. However, a more pronounced decrease in speed and accuracy was reported postflight, possibly due to re-exposure and adjustment to Earth’s gravity, and the busy schedule that enveloped Scott after his mission."

Download Center

HTML - No Current Item Deck
  • Free Safety Management Software Demo

    IndustrySafe Safety Management Software helps organizations to improve safety by providing a comprehensive toolset of software modules to help businesses identify trouble spots; reduce claims, lost days, OSHA fines; and more.

  • Complete Online Safety Training Courses

    Deliver state-of-the art, online safety training courses to your organization with IndustrySafe Training Management Software. Generate reports to track training compliance and automatically notify learners of upcoming or overdue classes.

  • Easy to Use Safety Inspection App

    Conduct inspections on the go with IndustrySafe’s mobile app. Complete safety audits at job sites and remote locations—with or without web access.

  • Track Key Safety Performance Indicators

    IndustrySafe’s Dashboard Module allows organizations to easily track safety KPIs and metrics. Gain increased visibility into your business’ operations and safety data.

  • Analyze Incident Data and Maintain OSHA Compliance

    Collect relevant incident data, analyze trends, and generate accurate regulatory reports, including OSHA 300, 300A, and 301 logs, through IndustrySafe’s extensive incident reporting and investigation module.

  • Industry Safe
comments powered by Disqus