The discovery is a boost for the Panspermia Hypothesis — but it's a potential nightmare for scientists concerned about interplanetary contamination.
European scientists have learned that artificial plasmid DNA — small loops of DNA — are capable of surviving a 13-minute trip into space and subsequent reentry. The result came as a complete surprise to the researchers.
The experiment was conducted on the TEXUS-49 sounding rocket, which is used for unoccupied, short-duration missions.
The University of Zurich scientists "painted" the bioengineered plasmids on the exterior of the rocket and onto a number of screw heads. During the flight, the genetic material attained a height of 166 miles (257 km), was subjected to 6.3 G's of thrust, six minutes of microgravity, and blazingly hot temperatures exceeding 1,000 degrees C.
After recovering the rocket, DNA was collected from all of the application sites. The researchers found that as much as 35% retained its full biological function ( i.e., mediating antibiotic resistance in bacteria and fluorescent marker expression in eukariotic cells). The highest rate of survival was found inside the grooves of the screw heads, which featured a 53% survival rate.
This surprising discovery is sure to upset space mission scientists. The revelation that genetic material is considerably hardier than previously thought means it has the potential to stow away on robotic landers bound for other worlds. De-contamination protocols will have to take this into consideration.
Ironically, it could make the search for alien life all the more difficult. Should we find DNA on another planet or comet, we may not be able to tell if it originated from Earth or if it's indigenous to that celestial body.
The discovery also provides a boost to the Panspermia Hypothesis, the suggestion that life on Earth was seeded by microbes from space. That said, unprotected DNA would probably be destroyed by UV radiation. Future experiments should thus be focused around this exact issue.
Read the entire study here.
Top photo: Adrian Mettauer. Other images via Thiel et al, PLOS.