Genetic materials of starry origin: study

June 14th, 2008 - 3:16 pm ICT by IANS  


London, June 14 (IANS) In a first, scientists have confirmed that an important component of early genetic material is extraterrestrial in origin. In a paper in the latest issue of the journal Planetary Science Letters,they have said that some of the raw materials that went into early genetic material have been found in meteorite fragments.

The materials include the molecules uracil and xanthine, precursors to the molecules that make up DNA and RNA, known as nucleobases.

The team discovered the molecules in rock fragments of the Murchison meteorite, which crashed in Australia in 1969.

They tested the material to determine whether the molecules came from the solar system or were a result of contamination when the meteorite landed on Earth.

The analysis shows that the nucleo-bases contain a heavy form of carbon that could only have been formed in space. Materials formed on Earth consist of a lighter variety of carbon.

Co-author Zita Martins of Imperial College London said that the research may 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.”

Between 3.8 to 4.5 billion years ago, many rocks similar to the Murchison meteorite rained down on Earth at the time when primitive life was forming.

The heavy bombardment would have brought large amounts of meteorite material to the surface on planets like Earth and Mars.

Co-author Mark Sephton, also of Imperial’s Department of Earth Science and Engineering, said this research was an important step in understanding how early life might have evolved.

“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.

“As more and more of life’s raw materials are discovered in objects from space, the possibility of life springing forth wherever the right chemistry is present becomes more likely,” he added.

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