Life on Earth was started by a meteorite, new evidence suggests

There are four such chemicals (adenine, thymine, cytosine and guanine, better identified by their initials, A, T, C and G) which are known as “bases” and their arrangement makes up an individual’s genome.

Every person’s order of these four bases is unique and provides the code for personality, appearance, health and everything in between.

Previously, scientists had found evidence of guanine and adenine in meteorites, but – despite intense searching – had never spotted their complementary partners.

A team of Japanese researchers, led by Hokkaido University, obtained two samples of the Murchison meteorite which landed in Australia in 1969 and one sample from both the Murray and Tagish Lake meteorites, which landed in the US in 1950 and Canada in 2000, respectively.

They were ground into a fine powder and subjected to hypersensitive analysis capable of detecting molecules at the parts-per-trillion level.

More than 30 chemicals were identified in total, including the four vital DNA ingredients.

“Given that extraterrestrial materials, including meteorites, were provided to the Hadean Earth at a flux much higher than that in the present day, a large number of these canonical base pairs may have also been delivered to the Earth at that time,” the researchers write.

“The accumulation of these scarce molecules has substantial geochemical challenges on Hadean Earth with an atmosphere possibly dominated by carbon dioxide and nitrogen.

“Hence, we expect that the exogenous base pairs contributed to the emergence of genetic properties for the earliest life on Earth.”

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