New Scientist
Image: NASA’s Marshall Space Flight Center
Talk about making an impact. One of the meteorites that slammed into the planet early in its history could have kick-started life: the collision may have generated all four of the bases in RNA.
Life appeared on Earth around 4 billion years ago, about the same time that the planet was experiencing a beating from large meteorites – an event called the Late Heavy Bombardment. As far as Svatopluk Civiš at the Academy of Sciences of the Czech Republic in Prague and his colleagues are concerned, that’s no coincidence.
They simulated a meteorite impact on early Earth by firing a high-power laser at samples of formamide – a liquid that would have existed on our primordial planet. The sample temperatures soared to 4200 °C, generating X-rays and extreme ultraviolet radiation that reacted with the formamide to create chemical radicals. These radicals, in turn, reacted with hydrogen and the remaining formamide to generate 2,3-diaminomaleonitrile – DAMN for short – which is a chemical precursor to the nucleobases.
When Civiš and his colleagues examined the end products of their reaction, they found all four RNA bases: adenine, guanine, cytosine and uracil – three of which are also found in DNA. Read more on newscientist.com…
