asteroid fragments contain one of the components of RNA, necessary for the appearance of life

Could an asteroid have brought life to Earth? Japanese scientists have discovered uracil, one of the components of RNA, in a 10 milligram sample present on the asteroid Ryugu, according to their study published Tuesday March 21 in Nature (in English). A previous analysis of the fragments of this asteroid already confirmed, the theory of an extraterrestrial origin of water. If the DNA, with its double helix, carries the genetic information, the RNA, made up of a single ribbon, is a messenger allowing the implementation of the instructions contained in the DNA.

It is made up of four bases: adenine, guanine, cytosine and uracil. This study is the latest to examine the 5.4 grams of fragments and dust recovered by the Japanese probe Hayabusa-2 on the asteroid Ryugu, ddiscovered in 1999 and located more than 300 million kilometers from our planet. Launched from Earth in 2014, Hayabusa-2 returned to Earth orbit in 2020 to release a capsule containing the sample.

“Strong Evidence”

The discovery lends credence to the theory, called panspermia, that life on Earth was “seeded” from space when asteroids crashed into the planet. This theory does not however exclude that of the appearance of life on Earth from the primitive oceans, or even its atmosphere.

She offers a “strong evidence that one of the components of RNA was delivered to Earth even before the emergence of life”, via a Ryugu-like asteroid that crashed into our planet, according to one of the study’s authors, Yasuhiro Oba, associate professor at Hokkaido University. He “Assumed” that such a deposit has “played a role in prebiotic evolution and possibly the appearance of life” on earth.

The other RNA components were not identified in the Ryugu samples, although the researcher does not rule out their presence, but at levels too low to be detectable. The professor hopes to be able to analyze other asteroid samples in the future, such as the one that the Osiris-REx probe must bring back from the asteroid Bennu, expected on Earth this year.