Washington, June 14 : Analysing the meteorite fragments that crashed in Australia in 1969, scientists have come to the conclusion that an important component of early genetic material might have originated from stars.
The scientists, from Europe and the USA, say that their findings indicate that parts of the raw materials to make the first molecules of DNA and RNA might come from sources beyond Earth.
The materials they have found include molecules uracil and xanthine, which are precursors to the molecules that make up DNA and RNA, and are known as nucleobases.
The team tested the rock fragments of the Murchison meteorite to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth.
The researchers found that nucleobases contain a heavy form of carbon, which could only have been formed in space because materials formed on Earth consist of a lighter variety of carbon.
Dr Zita Martins of the Department of Earth Science and Engineering at Imperial College London, lead author of the study, said that the research might provide another piece of evidence explaining the evolution of early life.
"We 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," she said.
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.
Professor Mark Sephton of Imperial's Department of Earth Science and Engineering, co-author of the study, said that the research was an important step in understanding the evolution of early life.
"Because 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," he said.
The research is published in the journal Earth and Planetary Science Letters.