Houston's George Fox and colleagues grew Escherichia coli for more than 1,000 generations in microgravity conditions, and, as they report in NPJ Microgravity, sequencing of the 1,000th generation uncovered 16 mutations, five of which affected coding regions. The genes affected are involved in pili biogenesis, bacterial adhesion, and osmotic stress response.
"We are, in fact, seeing true genomic changes — permanent changes," Fox tells New Scientist. He adds, that though they've uncovered genes that mutate under these conditions, "we don't know what they're doing exactly."
Still, the microgravity-adapted strain outcompeted a strain not grown in such conditions, even after being returned to normal gravity conditions for 30 generations. This suggested to the researchers that these changes were permanent. They also note that the microgravity-adapted strain did not develop antibiotic resistance.
"We need more of this kind of experiment, especially with human space flight gaining more traction in recent years," first author Madhan Tirumalai, also from Houston, adds at New Scientist.