Fascinating report on the origins of some of the building blocks for nucleic acids. Dr Zita Martins, of the Department of Earth Science and Engineering at Imperial College London and colleagues report finding the nucleobases xanthine and uracil in meteor fragments. The nucleobases contain an isotope of carbon that is not present on earth, ruling out earthly origins for their findings. Could it really be that the antecedents of life here on earth were extraterrestrial?
Lead author Dr Zita Martins, of the Department of Earth Science and Engineering at Imperial College London, says that the research may provide another piece of evidence explaining the evolution of early life. She says:
â€œWe believe early life may have adopted nucleobases from meteoritic fragments for use in genetic coding which enabled them to pass on their successful features to subsequent generations.â€?
Between 3.8 to 4.5 billion years ago large numbers of rocks similar to the Murchison meteorite rained down on Earth at the time when primitive life was forming. The heavy bombardment would have dropped large amounts of meteorite material to the surface on planets like Earth and Mars.
Co-author Professor Mark Sephton, also of Imperialâ€™s Department of Earth Science and Engineering, believes this research is an important step in understanding how early life might have evolved. He added:
â€œBecause meteorites represent left over materials from the formation of the solar system, the key components for life -- including nucleobases -- could be widespread in the cosmos. As more and more of lifeâ€™s raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely.â€?
MARTINS et al. Extraterrestrial nucleobases in the Murchison meteorite. Earth and Planetary Science Letters, 2008; 270 (1-2): 130 DOI:10.1016/j.epsl.2008.03.026