DNA can survive critical conditions in space

The genetic material DNA can survive a flight through space and re-entry into Earth's atmosphere - and still pass on genetic information, scientists have found.
The discovery was made by scientists from the University of Zurich in Switzerland during an experiment on the TEXUS-49 research rocket mission.
Small, double-stranded DNA molecules that were applied to the outer shell of the payload section of a rocket using pipettes flew into space from Earth and back again.
After the launch, space flight, re-entry into Earth's atmosphere and landing, the so-called plasmid DNA molecules were still found on all the application points on the rocket from the TEXUS-49 mission.

For the most part, the DNA salvaged was still able to transfer genetic information to bacterial and connective tissue cells.
"This study provides experimental evidence that the DNA's genetic information is essentially capable of surviving the extreme conditions of space and the re-entry into Earth's dense atmosphere," said study head Professor Oliver Ullrich from the University of Zurich's Institute of Anatomy.

The experiment called DARE (DNA atmospheric re-entry experiment) resulted from an idea by UZH scientists Dr Cora Thiel and Ullrich who were conducting experiments on the TEXUS-49 mission to study the role of gravity in the regulation of gene expression in human cells using remote-controlled hardware inside the rocket's payload.

During the mission preparations, they began to wonder whether the outer structure of the rocket might also be suitable for stability tests on so-called biosignatures.
"Biosignatures are molecules that can prove the existence of past or present extraterrestrial life," said Thiel.
The two researchers launched a small second mission at the European rocket station Esrange in Kiruna, north of the Arctic Circle.
The additional experiment was originally supposed to be a pretest to check the stability of biomarkers during spaceflight and re-entry into the atmosphere.
"We were completely surprised to find so much intact and functionally active DNA," said Thiel.

Various scientists believe that DNA could certainly reach us from outer space as Earth is not insulated: in extraterrestrial material made of dust and meteorites, for instance, around 100 tonnes of which hits our planet every day.
The extraordinary stability of DNA under space conditions also needs to be factored into the interpretation of results in the search for extraterrestrial life, researchers said.
"The results show that it is by no means unlikely that, despite all the safety precautions, space ships could also carry terrestrial DNA to their landing site. We need to have this under control in the search for extraterrestrial life," said Ullrich.