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Astronauts' genes 'mutate'
07/11/2006 09:36 - (SA)
Essen - Space flight leads to significant genetic mutations in astronauts because of cosmic rays, a German scientist warned on Monday after a study of 12 space travellers.
The geneticist, Christian Johannes of Essen-Duisburg University, said the rays even damaged chromosome material at relatively low orbits, just 500 kilometres above the surface of the Earth.
Johannes is studying blood cells obtained from astronauts before and after their space travel.
"On average, the proportion of cells with altered chromosomes rises from one percent to about 1.5 percent. This represents an increase of 40%," he said. Such alterations brought a greater danger of cancer.
The study is to continue for a further two years and aims to cover at least 20 astronauts.
Johannes said the proportion of altered material declines again six months and 12 months after the astronauts return to Earth, thanks to self-repair mechanisms in cells.
On the ground, humans are protected from cosmic particles by the planet's atmosphere. - Sapa-dpa
- SAPA
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