As you surely know, DNA which acts as a genetic plane and RNA as a decoder of this plane represent the fundamental elements of the genetic inheritance essential to all biological life. Until now, it has always been thought that RNA developed first on our planet and that DNA evolved just after it.
However, several pieces of evidence reveal that these two elements, involved in the birth of life on Earth, may well have evolved at the same time and therefore coexisted .
This hypothesis is supported by a study that explains how the diamidophosphate (DAP) that may have preceded life on our planet can connect DNA building blocks called deoxynucleosides into basic DNA strands.
This suggests that the same type of chemical reactions could have led to the simultaneous development of DNA and RNA at the beginning of life on Earth, to give rise to the first self-replicating molecules.
Life on Earth couldn't come from RNA alone
According to Ramanarayanan Krishnamurthy, a chemist at Scripps Research (Calif.), The discovery is an important step towards the design of a detailed chemical model of the origin of the first forms of life on Earth.
Thus, RNA could not have gone through the self-replication process without the intervention of enzymes believed to have evolved after it. Several studies and recent experiments show that DNA could well have coexisted with RNA in the engineering of life by creating strands of "chimeric" molecules capable of separating more easily.
Finally, very revealing experiences concerning DNA and RNA
The researchers have indeed simulated with a series of laboratory tests what could have happened before the appearance of life on Earth. They then demonstrated that in the same way that RNA can come together from chemical building blocks, basic DNA could have been formed thanks to DAP.
This discovery, which shows us insight into the RNA-DNA relationship, is useful for a multitude of applications in modern chemistry and biology, not just for understanding the origins of life.
Krishnamurthy and his team hope that they can start using this chemistry on mixtures of ribonucleosides and deoxynucleosides to find out which chimeric molecules will form and if they are able to self-replicate and evolve, to finally explain how life came to be. on our planet.