US chemists have made a discovery that supports a new theory that life on the planet arose from a mixture of RNA and DNA. The finding could suggest new practical applications in chemistry and biology.
A simple compound called diamidophosphate (DAP) that was present on #Earth before life originated could have chemically bonded small building blocks of ADN. These blocks are called deoxynucleosides, explain the scientists at the #Scripps #Research #Center in their study published in the journal #Angewandte #Chemie.
#This new finding points to the possibility that DNA and its biological cousin, RNA, appeared together as products of similar chemical reactions and that the first self-replicating molecules, that is, the first forms of life on the planet, were mixtures of both.
The discovery addresses one of humanity’s most recurring questions: how life originated on our planet. #In particular, it opens the way for more extensive research on how self-replicating DNA and RNA mixtures could have evolved and spread across the planet.
“#This finding is an important step toward developing a detailed chemical model of how the first forms of life originated on #Earth,” says lead study author #Ramanarayanan #Krishnamurthy, associate professor of chemistry at the #Scripps #Research #Center. .
The finding also questions the most popular hypothesis in recent decades, which states that the first replicators were based on RNA, and that DNA later emerged as a product of the life forms of its biological cousin.
#However, #Krishnamurthy and others partially questioned this idea, because the RNA molecules might have been too “sticky” to serve as the first self-replicators.
The scientist and his colleagues showed in recent studies that the “chimeric” molecular strands that are part of DNA and RNA can mold complementary strands in a less sticky way, allowing them to separate with relative ease.
The experts also confirmed in their papers that the building blocks of ribonucleosides and simple deoxynucleosides, of RNA and DNA respectively, could have arisen under very similar chemical conditions on #Earth.
#In 2017 specialists reported that the organic compound DAP could have played an important role when it comes to ribonucleosides and unite them in the first strands of RNA. The new study, in turn, shows that under similar conditions DAP could have done the same with DNA.
“#Now that we better understand how a primordial chemistry could have formed the first DNA and RNA, we can begin to use it in mixtures of ribonucleoside and deoxynucleoside building blocks to see which chimeric molecules form, and if they can self-replicate and evolve,” #Krishnamurthy explains.
The expert emphasizes that such a study could have broad practical applications. #Artificial synthesis of DNA and RNA, for example in PCR tests for COVID-19, is part of a global business, but it relies on enzymes that are relatively fragile and have many limitations. #Enzyme-free chemical methods for producing DNA and RNA may prove to be more attractive in most cases, he says. #Krishnamurthy.
#Previously, several #Russian scientists found cyclophosphates for the first time in nature. These are the possible precursor substances of the molecules that contain phosphorus and that participated in the formation of the first forms of life on our planet.
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#study #sheds #light #life ##Earth