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Radiation effects in nematodes: results from IML-1 experiments
G A Nelson1, W W Schubert, G A Kazarians
1Jet Propulsion Laboratory, California Institute of Technology, Pasadena 91109, USA.
Advances in Space Research : the Official Journal of the Committee on Space Research (COSPAR)
|October 1, 1994
Summary
Space radiation significantly increased mutation rates in Caenorhabditis elegans (nematode worms). Dormant worms exposed to cosmic rays showed an 8-fold higher mutation frequency compared to ground controls, indicating space radiation
Area of Science:
- Space Biology
- Radiation Biology
- Genetics
- Astrobiology
Background:
- Understanding the biological effects of space radiation is crucial for human space exploration.
- Caenorhabditis elegans is a valuable model organism for studying genetic mutations due to its genetic tractability and short life cycle.
- Previous studies have indicated potential genetic damage from space environments, but direct correlation with specific radiation types remains an area of active research.
Purpose of the Study:
- To investigate the genetic effects of natural space radiation on dormant Caenorhabditis elegans.
- To correlate the fluence of high-charge and high-energy (HZE) particles with specific genetic mutations.
- To quantify mutation rates in essential genes and the unc-22 structural gene following space exposure.
Main Methods:
- Dormant Caenorhabditis elegans were exposed to space radiation aboard the International Microgravity Laboratory 1 (STS-42) using the ESA Biorack.
- Animals were suspended in buffer or on agar, or immobilized adjacent to CR-39 plastic nuclear track detectors.
- Mutations were isolated in a set of 350 essential genes and the unc-22 gene; lethal mutations were identified using a balanced translocation (eT1(III;V)).
Main Results:
- Thirteen mutants in the unc-22 gene and 53 lethal mutations were isolated from flight samples.
- Preliminary analysis suggests a higher proportion of rearrangements in mutants correlated with cosmic ray tracks compared to random samples.
- The mutation rate in flight samples was approximately 8-fold higher than in ground controls, which showed spontaneous frequencies.
Conclusions:
- Natural space radiation significantly elevates the mutation rate in Caenorhabditis elegans.
- Specific cosmic ray events may be associated with a higher incidence of genetic rearrangements.
- These findings highlight the genotoxic potential of space radiation and underscore the need for radiation protection strategies in space missions.