What effects do changes in gravity have on DNA replication?
The major point of concern regarding the fidelity of DNA replication in space is not microgravity itself, but rather cosmic radiation. The average dose of radiation received by an astronaut while on the Shuttle is significantly higher than what they would experience on Earth in a year. A radiation biology experiment performed on C. elegans, a microscopic worm, flown on the Shuttle showed the rate of mutagenesis to be significantly higher in space than in the ground controls. Studies have also been done on the effects of microgravity on cell division and DNA replication. Cells with chromosome breaks, bridges, and double nuclei were found in space samples and quantified. None of these abnormalities were evident in the ground controls. However, it is not known if these effects were due to microgravity or radiation exposure.
