Space travel could cause gene malfunctions in astronauts
Experiment shows wide genetic changes after long-term weightlessness
Reproduction and immune system changed
Experiment with flies kept ‘weightless’ in a magnetic field
By Rob Waugh
Last updated at 11:50 AM on 1st February 2012
Astronauts on long space journeys such as a mission to Mars could experience genetic malfunctions, say scientists.
Experiments using magnetic fields to simulate long-term weightlessness found that being weightless caused genes to malfunction – affecting genes involved in reproduction, the immune system and stress.
The researchers used flies in the experiment, as their rapid life cycles and small size makes them ideal. The experiments were conducted on Earth using superconducting magnets.
Flies an be ‘levitated’ on earth using strong magnetic fields to repel the water in their bodies.
Their rapid life-cycle allows scientists to assess effects that would be ‘long-term’ in humans.
This 22-day study revealed unexpected gene malfunctions in the flies from the prolonged weightlessness.
The number of flies born dropped radically, and genes affecting the immune system were also affected.
The results are said to have important implications for prolonged manned space flight, for instance a journey to Mars.
Flies are levitated with magnets to simulate the effects of prolonged weightlessness: This 22-day study revealed unexpected gene malfunctions in the flies
The scientists found evidence of widespread disruption of cell processes.
Activity of several genes was affected, including those involved in cell-signalling, the immune system, and responses to stress and temperature changes.
Researchers used a specially designed superconducting magnet generating a field that repelled water in the flies’ body.
By adjusting the field, they were able to cancel out the effect of gravity.
Flies were continuously ‘levitated’ for 22 days throughout their life cycle.
Genes were found to be sensitive to the magnetic field as well as the effects of weightlessness.
Almost 500 genes were made more or less active by the field, which slightly delayed progress from egg to adult.
By studying the flies at normal gravity, zero gravity and 2G, or double the Earth’s gravity, the scientists were able to isolate gravity’s effects on the flies.
Boosted gravity altered the activity of 44 genes, while weightlessness affected more than 200, the scientists reported in the journal BMC Genomics.
Dr Raul Herranz, from the Centre of Biological Investigation in Madrid, Spain, said: ‘Both the magnetic field and altered gravity had an effect on gene regulation for the flies.
‘The results of this can be seen in fly behaviour and in successful reproduction rates. The magnetic field alone was able to disrupt the number of adult flies from a batch of eggs by 60%.’
‘However the concerted effort of altered gravity and the magnet had a much more striking effect, reducing egg viability to less than 5%.’
He added: ‘The genes most affected by alterations in gravity are responsible for essential cellular processes including metabolism, the immune system, defence against fungi or bacteria, heat response, and cell signalling.’