Washington, Aug 9:  Meteorites were possibly the source of first life on earth, says a new research.
 Scientists have been trying for long to figure out whether nucleobases, our genetic building blocks, rode to earth on meteorites, especially the organic rich ones called carbonaceous chondrites.
 "Finding nucleobase compounds not typically found in Earth's biochemistry strongly support an extraterrestrial origin," said Jim Cleaves of Carnegie Institute's Geophysical Lab, who led the study.
 Amino acids, which string together to form proteins, are known to exist in space and have reached our planet piggybacking on carbonaceous chondrites, the journal Proceedings of the National Academy of Sciences reports.
 But it has been difficult to similarly prove that the nucleobases found on meteorite samples are not due to contamination from sources on earth.
 The research team, which included Cleaves, used advanced spectroscopy techniques to purify and analyze samples from different carbonaceous chondrites and one ureilite, a very rare type of meteorite with a different chemical composition.
 These results show the earliest forms of life on earth may have been assembled from materials delivered to Earth by meteorites.
 "This shows us that meteorites may have been molecular tool kits, which provided the essential building blocks for life on Earth," Cleaves said. IANS

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