TEXUS 50 rocket engine. Image: DLR
DNA has traveled to space and back and lived to tell the tale. Of course, DNA travels to space on a regular basis and has been doing so for as long as living things have been blasted into orbit, but this is different. This particular DNA was on the outside of the rocket, an unprotected hitchhiker open to whatever extreme environment it should encounter.The experiment above was conducted fairly recently, the work of a team of biologists based at the University of Zurich who had gained unexpected access to what's known as a sounding rocket. This is a vessel designed to make only short journeys into suborbital space and back, usually with intention of snagging some measurements and immediately returning to Earth. The TEXUS 49 flight, which hosted the Zurich team's biological payload in 2011, was part of a series designed to explore the effects of microgravity.The DNA that made the journey was an artificial plasmid, a sort of genetic material that exists within in a cell independently from the cell's main DNA package, possibly conferring an extra/bonus ability such as antibiotic resistance. These particular plasmids were created with a fluorescent marker and were affixed to the rocket's exterior in a number of locations, including the bare exterior of its payload and within the grooves of the screw-heads found on one of the payload's experimental modules.The viability of organisms and bare DNA in space has been tested before many times, particularly in experiments based at the International Space Station. Moreover, the survivability of a re-entry into Earth's atmosphere has been tested, albeit so far with more negative results. As the Zurich biologists explain, testing the viability of life in the extreme conditions of atmospheric re-entry will take many more experiments, a frequency that's been difficult to achieve. So, the crux of the Swiss team's research is the suggestion that sounding rockets might be the scientific platform needed.Upon returning home, the TEXUS 49 DNA was tested for functionality. The biologists implanted E. coli bacteria with the plasmids and watched to see if the bacteria would adopt the antibiotic resistance abilities that would ordinarily be encoded within the plasmid DNA. Some but not all of the DNA was successful. The more protected the genetic material was, the more ability it had to develop bacterial colonies."We demonstrated stability and functional activity of DNA during hypervelocity atmospheric transit," the Zurich biologists write. "We could further show that up to 35 percent of DNA retained its full biological function, i.e., mediating antibiotic resistance in bacteria and fluorescent marker expression in eukariotic cells."
