All four major components of DNA have been detected in rocks from outer space, according to a new study.
These findings suggest that the building blocks of life may have been delivered to Earth by ancient extraterrestrial objects.
Scientists led by Yasuhiro Oba, a professor at Hokkaido University, say that they've detected trace amounts of cytosine and thymine in three carbonaceous (carbon-rich) meteorites, which feeds into the idea that extraterrestrial impacts 'contributed to the emergence of genetic properties for the earliest life on Earth', according to a study published in the journal Nature Communications.
The breakthrough came about after the team analysed samples from various meteorites, which landed in Australia, Oklahoma, and British Columbia, as reported by Vice.
Oba’s team said: "The lack of pyrimidine diversity in meteorites remains a mystery since prebiotic chemical models and laboratory experiments have predicted that these compounds can also be produced from chemical precursors found in meteorites.
"Here we report the detection of nucleobases in three carbonaceous meteorites using state-of-the-art analytical techniques optimized for small-scale quantification of nucleobases down to the range of parts per trillion (ppt).
"In addition to previously detected purine nucleobases in meteorites such as guanine and adenine, we identify various pyrimidine nucleobases such as cytosine, uracil, and thymine.
"This study demonstrates that a diversity of meteoritic nucleobases could serve as building blocks of DNA and RNA on the early Earth."
They concluded: "Looking ahead to the next decade in combination with laboratory-based analysis and model simulation studies, we are now approaching a more complete understanding of the molecular distributions of meteoritic organics, including nucleobases and their formation pathways.
"Given that extraterrestrial materials, including meteorites, were provided to the Hadean Earth at a flux much higher than that in the present day."
A lot to digest there but it's important to note that next year's sample-return missions, such as NASA’s OSIRIS-REx, will deliver pristine material from a carbonaceous asteroid to Earth.
Basically, the missions will help firm up how life on Earth began.
Let's just be grateful that we only have to read about it, rather than working out all the science...
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