The bacterium, known as "Deinococcus radiodorans", can survive radioactive radiation a thousand times stronger than that which causes death to humans. The researchers claim that the bacterium began its life on Mars before reaching Earth via an asteroid
Russian scientists claim that the origin of a bacterium with high resistance to radioactive radiation may be from the planet Mars. The bacterium, known as "Deinococcus radiodorans", can survive radioactive radiation a thousand times stronger than that which causes death to humans. The researchers claim that the bacterium began its life on Mars before reaching Earth via an asteroid.
The magazine "New Scientist" reports this week that in order to test how the "deinococcus" developed its high resistance to radiation, a team of scientists from St. Petersburg bombarded a "coli" bacterium of type E with gamma rays. The bacteria of this type were exposed to an amount of radiation that killed 99.9% of them. The surviving bacteria are given time to recover and multiply,
before being exposed to a higher amount of radiation. After 44 cycles, in which the bacteria were exposed to increasing amounts of radiation, a radiation intensity 50 times greater than the original was needed to kill the same relative amount of bacteria. That is, the bacteria that survived each cycle were more immune to radiation.
The researchers found that they would have to perform another thousand radiation cycles for the "Coli" to develop a resistance identical to that of the "Deinococcus". This means that to develop such resistance on Earth, a period of 100 million years is needed, but on Mars the bacteria can be exposed to the required amount of radiation within a few hundred thousand years. This finding led the researchers to conclude that the "Deinococcus" evolved on Mars before being thrown into space by an asteroid and landing on Earth on a meteorite.
David Meerson, a NASA astrobiologist, argued in response to the experiment's findings that it is unlikely that the "deinococcus" came from Mars because, according to him, its genetic structure is the same as that of other bacteria on Earth. However, he was unable to explain how the "Deinococcus" is so resistant to radioactive radiation. "It's definitely a mystery how it survives," Morrison told New Scientist.
For news in the New Scientist
