AstroTalk - March - 29 - 14 - 00 - 00 by MarcoDeepi1 published on 2018-06-01T02:16:38Z Peggy Whitson has just come back from n space. The astronaut has set a record for the length of a spacewalk, and the longest duration in space for any US astronaut, at 665 days. Mark and Scott Kelly are now re-united. Scott Kelly spent 1 year in space, while his twin brother, Mark, stayed on Earth. During this time, any potential changes in Scott's genes, or gene expression, was measured. Telomeres and Telomerase of genes were focused on. It is understood that when looked at over many years, telomeres decrease in length as a person ages. Interestingly, on a time scale of just one year, Bailey found Scott’s telomeres on the ends of chromosomes in his white blood cells increased in length while in space. This could be linked to increased exercise and reduced caloric intake during the mission. However, upon his return to Earth they began to shorten again. There was also a decrease in Scott's bone formation during his last 6 months in space. In the DNA within Scott’s white blood cells, he found that the level of methylation, or chemical modifications to DNA, decreased while inflight – including a gene regulating telomeres, but returned to normal upon return. On the ground, Mark’s level of methylation in the DNA derived from his white blood cells increased at the midpoint of the study but returned to normal in the end. Variability was observed in the methylation patterns from both twins; however, this epigenetic noise was slightly higher in Scott during spaceflight and then returned to baseline levels after return to Earth. These results could indicate genes that are more sensitive to a changing environment whether on Earth or in space. Other long term changes will appear in upcoming articles. James Webb Space Telescope's launch has been delayed again, until may 2020.