PDF version of COSPAR - Space Science Research in Canada Report

also low-maintenance; they live in small bags and feed on a special chemical dietthat is automatically changed by a machine every six weeks. The chemical diet,developed by Nate Szewczyk of the University of Pittsburg, is a key componentthat allows the worms to reproduce in space.“These very small animals are easily cultured in space with equipment that canbe completely automated so we don’t have to devote a lot of crew time to culturethem,” said Cohen.Another important element of the experiment is the use of a particular strain of C.elegans, appropriately named eT1. Developed by research associates RajaRosenbluth and Bob Johnsen from Simon Fraser University in British Columbia,its most significant feature is that it allows the researchers to capture andpreserve genetic mutations through many generations.Normally, genetic damage tends to eliminate itself over time, Bailie said.“Damaged DNA leads to damaged genes, which leads to damaged animals, anddamaged animals die.”However, geneticists have used a “genetic trick,” a process called balancing, thatenables them to preserve a multigenerational record of genetic mutations in C.elegans. “It allows you to keep the damaged DNA copy over a copy of good DNAand allows you to keep the animals alive so you can analyze then,” Baillie said.“We can keep the damaged DNA so we know where it is. We’ll return the animalsalive to earth and determine what mutations they picked up when they were inspace.”The DNA of the space worms will be compared to bits of DNA from normalworms contained on a newly developed device called a DNA-array chip. Bailliesaid this “bleeding-edge” technology allows them to quickly identify mutations,reducing the “people-time” it takes to analyze the DNA from months to hours.Baillie’s team has already demonstrated that they can indeed capture what hecalls “space mutants,” using samples of the eT1 strain that were flown onmissions in 1992, 1996 and 2004. “Our strain works as we designed it to work forcapturing mutations,” he said.However, these animals were only briefly exposed to space radiation (the longestflight was 11 days), so there were only a few mutations, not much more thanwhat occurs spontaneously on Earth. Baillie needed to park the worms on theSpace Station for months at a time to gain a better understanding of the potentialradiation threat posed by long-duration flights.37