Space-ship Mir Wheat Experiment
A closed system experiment was carried out February-May, 2005 to grow 3rd generation Mir wheat seeds to 4th generation. These plants were grown alongside control plants – plants of the same species that were grown on earth. Tissue from both the Mir generation plants and earth-based plants were collected for analysis to test an hypothesis that plants grown in space will pass on a cellular memory of being in zero-g to successive generations and these generations will express the trait even though they are grown on earth. The experiment was conducted by Biosphere Foundation and Biospheric Design with Galina Nechitailo, Biotechnika Russian State Institute, and scientists at the University of Florida. Rob Ferl and Anna-Lisa Paul, University of Florida, will look at the gene expression profiles of Apogee wheat grown from the Mir-raised seed and the Apogee control. In the photo above, the small plant to the left is the 4th generation wheat seed from Mir. The wheat plant just to its right, is the control wheat.
Once it was established that the spaceflight environment was not a drastic impediment to plant growth, a remaining space biology question was whether long-term spaceflight exposure could cause changes in subsequent generations, even if they were returned to a normal Earth environment. In this study, we used a genomic approach to address this question. We tested whether changes in gene expression patterns occur in wheat plants that are several generations removed from growth in space, compared to wheat plants with no spaceflight exposure in their lineage. Wheat flown on Mir for 167 days in 1991 formed viable seeds back on Earth. These seeds were grown on the ground for three additional generations. Gene expression of fourth-generation Mir flight leaves was compared to that of the control leaves by using custom-made wheat microarrays. The data were evaluated using analysis of variance, and transcript abundance of each gene was contrasted among samples with t-tests. After corrections were made for multiple tests, none of the wheat genes represented on the microarrays showed a statistically significant difference in expression between wheat that has spaceflight exposure in their lineage and plants with no spaceflight exposure. This suggests that exposure to the spaceflight environment in low Earth orbit space stations does not cause significant, heritable changes in gene expression patterns in plants.
Visscher, A., A-L. Paul, M. Kirst, A. K. Alling, S. Silverstone, G. Nechitailo, M. Nelson, W.F. Dempster, M. Van Thillo, J. P. Allen, R. J. Ferl. 2009. Effects of a Spaceflight Environment on Heritable Changes in Wheat Gene. Astrobiology May 9 (4): 359-67.