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New Analysis of the Murchison Meteorite Reveal the Building Blocks of Life

In research funded by the NASA Astrobiology Institute a new study of microfragments of a meteorite have revealed DNA components and other essential components of life - according to a team of scientists at NASA's Goddard Space Flight Center.

Researchers analysing the carbonaceous chondrite meteorites found DNA components and amino acids components during the analysis of the Murchison meteorite - a rock that fell to Earth over Murchison, Victoria, in Australia in September 1969.

This is important because amino acids are used to make proteins which are considered to be the most important molecules in life. They are used to make structural materials like skin and hair, and are also able to regulate chemical reactions.

The scientists also found components used to make DNA, the molecule that carries genetic information. Other molecules found included other biologically important molecules such as nitrogen heterocycles, sugar-related organic compounds, and also compounds found in modern metabolic processes.

Carbonaceous chondrite meteorites (carbon-rich meteorites) are relatively rare and comprise less than five percent of recovered meteorites. The are thought have formed around the same time as the Earth's formation 4.6 billion years ago.

This recent discovery expands on previous studies in cataloging the array of life molecules in this meteorite. The work lends yet more credence to the theory of cometary panspermia in which life on Earth was seeded by biological material falling to earth from the end of the late heavy bombardment approximately 4.6 billion years ago

"Despite their small size, these interplanetary dust particles may have provided higher quantities and a steadier supply of extraterrestrial organic material to early Earth,"
- Michael Callahan of NASA's Goddard Space Flight Center.

"Unfortunately, there have been limited studies examining their organic composition, especially with regards to biologically relevant molecules that may have been important for the origin of life, due to the miniscule size of these samples."

Callahan and his team at Goddard's Astrobiology Analytical Laboratory applied advanced analytical chemistry methods to probe tiny meteorite samples for the components of life:

"We found amino acids in a 360 microgram sample of the Murchison meteorite," said Callahan. "This sample size is 1,000 times smaller than the typical sample size used." 

"I'm particularly interested in analyzing cometary particles from the Stardust mission... It's one of the reasons why I came to NASA. When I first saw a photo of the aerogel used to capture particles for the Stardust mission, I was hooked."

"This technology will also be extremely useful to search for amino acids and other potential chemical biosignatures in samples returned from Mars and eventually plume materials from the outer planet icy moons Enceladus and Europa," - Astrobiologist Daniel Glavin, co-author of the paper.

"Missions involving the collection of extraterrestrial material for sample return to Earth usually collect only a very small amount and the samples themselves can be extremely small as well... The traditional techniques used to study these materials usually involve inorganic or elemental composition. Targeting biologically relevant molecules in these samples is not routine yet. We are not there either, but we are getting there."