The Identical Astronaut Twins Are Still Identical

Keith's note: You may have seen a lot of stories recently in major news publications over the past week or so stating that the Kelly brothers now have different DNA or something to that effect. Not true. Another example of reporters writing stories about something that they simply do not understand (I am an actual biologist so I can say that). Scott Kelly's DNA did not change. How some of his DNA is expressed (or not expressed) changed as a result (apparently) of spending nearly a year in space. But again, his DNA did not change. He and his brother are just as identical genetically as they were before he left Earth. Here is what NASA JSC PAO sent to some news media (but not others) on this topic:

"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. 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. We are at the beginning of our understanding of how space flight 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."

NASA Twins Study Confirms Preliminary Findings, NASA

"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."

Keith's note: Scott Kelly's genes i.e. the DNA sequence in his genome did not change so genes could not "return to normal". Nor are there any "changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia." Rather, how the genes are expressed was changed and that expression changed over time with some changes reverting to preflight expression while others have not. But the genes are not changed.

No, Scott Kelly's Genes Were Not Changed, earlier post

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This page contains a single entry by Keith Cowing published on March 15, 2018 5:37 PM.

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