Are we all aliens?
Life, after all, could well have originated in space! Research has indicated that the building blocks of our genetic material reached the Earth on meteorites in greater diversity.Updated: Aug 10, 2011 17:21 IST
Life, after all, could well have originated in space, at least in theory.
Scientists have detected the building blocks of DNA in meteorites since the 1960s, but were unsure whether they were created in space or resulted from the contamination by terrestrial life.
But now, NASA-funded researchers have found more evidence that meteorites can carry DNA components created in space.
The latest research has indicated that certain nucleobases - the building blocks of our genetic material - reach the Earth on meteorites in greater diversity and quantity than previously thought.The discovery has added to a growing body of evidence that the chemistry inside asteroids and comets is capable of making building blocks of essential biological molecules.
In the new work, scientists analyzed samples of 12 carbon-rich meteorites, nine of which were recovered from Antarctica. The team found adenine and guanine, which are components of DNA nucleobases.
Also, in two of the meteorites, the team discovered for the first time trace amounts of three molecules related to nucleobases that almost never are used in biology. These nucleobase-related molecules, called nucleobase analogs, provide the first evidence that the compounds in the meteorites came from space and not terrestrial contamination.
“You would not expect to see these nucleobase analogs if contamination from terrestrial life was the source, because they''re not used in biology,” said Michael Callahan, astrobiologist and lead author of the paper from NASA''s Goddard Space Flight Center in Greenbelt, Md.
“However, if asteroids are behaving like chemical ''factories'' cranking out prebiotic material, you would expect them to produce many variants of nucleobases, not just the biological ones, because of the wide variety of ingredients and conditions in each asteroid,” Callahan added.
The findings will be detailed in the online edition of the Proceedings of the National Academy of Sciences.