On Tuesday, March 18, 2025, Sunita William returned to Earth after a long 9-month wait. Thanks to NASA’s constant approach to the mission supported by SpaceX. Now, all the astronauts will remain under medical observation for a long time.
Astronauts experience muscle and bone loss due to prolonged exposure to microgravity in space and also have to face various other health-associated issues. Meaning, they can’t even walk normally after returning to Earth.
Research suggests that space’s cosmic radiation and microgravity and even spaceflight duration have a significant biological risk and produce problems for astronauts’ health. This means that it must have a serious impact on our genetics at a molecular level.
Let’s review several research works and try to understand if space travel, and staying at an International space station and spaceflight does have any impact on our DNA or not.
Key Topics:
Space environment
Our (Earth’s) environment significantly influences gene expression and helps us to adapt to the present conditions. However, the space environment is entirely different from Earth’s environment.
Earth has its gravitational field and a firm atmosphere, which collectively help organisms to survive on Earth. On the other hand space’s micro or nearly zero gravitational field and cosmic radiation are not suitable for us.
Where microgravity alters our gene expression by experiencing negative environmental factors, cosmic and space radiation can directly mutate the DNA.
The effect of space on Human DNA
Human DNA is a highly sensitive and dynamic biomolecule, a microchange in the environment or surroundings poses a significant shift in genetic mechanisms and regulations.
Space and the ISS (International Space Station) are a unique place for human DNA. Previously, NASA conducted a twin study to evaluate the impact of space travel and space stay on human DNA.
They reported gene expression changes between twin brothers Scott Kelly (who stayed in space for a year) and Mark Kelly (who stayed on Earth). Interestingly, Scott’s telomere shortening process was slower down compared to Mark’s on Earth. It took months for Scott’s genes to recover normal expression.
Space’s microgravity is responsible for epigenetic changes in human DNA. that, eventually, alter the gene expression profile of various genes and increase the risk of conditions like cancer.
Studies further demonstrate the downregulation of muscle and bone maintenance genes causing low bone and muscle density. In addition, over-activation of stress-related genes and altered immune system gene response are also evident in astronauts’ DNA.
Moreover, a study showed an increased DNA polymerase error rate in microgravity. This educates that our DNA damage repair systems can’t even work efficiently in such harsh conditions.
Our DNA mutates continuously!
Thanks to our DNA repair systems, equipped with single- and double-stranded break repair machinery, this synchronized system repairs DNA mutations and replication errors, and maintains DNA integrity.
Space’s cosmic radiation can directly damage our DNA. The high sun radiation (protons released from the large solar particle events) and far galaxies (galactic cosmic rays) radiation mutate our DNA, disrupt our DNA repair system and increase the risk of cancer-like conditions.
Ground-based microgravity analog studies further reveal oxidative DNA damage under microgravity. This causes single-stranded DNA damage and accelerates aging, inflammation and neurodegenerative conditions.
The same study on proliferative lymphocytes showed that microgravity, space flight and cosmic radiation also negatively influence the DNA double-stranded break repair, base excision repair and nucleotide excision repair pathways, and also downregulates genes involved in the same pathways.
Cosmic radiation also produces chromosomal aberrations, chromosomal or genomic instability and telomere shortening process. Such consequences aren’t observed immediately but only after 3 to 6 months, the same research paper further reported.
DNA fragmentation, DNA polymerase abnormalities and increased p53 mRNA levels have also been reported immediately after 48 hours of spaceflight. This can disrupt the programmed cell death process (apoptosis) and increase the likelihood of cancer.
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- How does Space Travel Affect Human DNA?
- Recent Genetic Research, Discoveries and News (January 2025)
- Sudden Cardiac Arrest in Young India: Is Genetics to Blame?
- Research Identified Novel Genetic Variants Linked to Skin Pigmentation
- Genetic Research Trends in 2023: A Data-Driven Study
Wrapping up:
In conclusion, space travel, microgravity, cosmic radiation and spacelight duration contribute to abnormal gene expression, DNA damage and faulty DNA repair systems. Such events can,
- Increase the risk of cancer.
- Immune dysfunction.
- Chances of infection (after returning to Earth).
- Cognitive and neurological problems.
- Muscle and bone weakening and dysfunction.
- Infertility and reproductive issues.
Space is an extreme environment that presents unique challenges to human health and biology. Upcoming moon and Mars mission success depends on this fact– how scientists deal with such problems.
Astronauts still need a more powerful suit that protects them against cosmic radiation, microgravity and other space-induced factors.
Sunita Williams and her colleagues’ return to Earth is a remarkable testament to human resilience, showcasing the power of a strong and determined mindset.
Best of luck to her and crew members for their future endeavors.
Resources:
Moreno-Villanueva, M., Wong, M., Lu, T. et al. Interplay of space radiation and microgravity in DNA damage and DNA damage response. npj Microgravity 3, 14 (2017). https://doi.org/10.1038/s41526-017-0019-7.
