DNA and RNA may have appeared on Earth at the same time

RNA and DNA may have arisen at the same time to form the building blocks for all life on Earth, according to a new study.

It’s the first time that researchers have been able to show that RNA and DNA could feasibly have come from the same precursor molecules and that even the earliest forms of life used both RNA and DNA in the same way that life on Earth does today.

The study was conducted by researchers from the Scripps Research Institute and published in the journal Nature Chemistry.

The results contradict the popular “RNA World” hypothesis which suggests that early life first used the simpler RNA and DNA only entered the picture later.

Even though most scientists agree with the “RNA World” hypothesis, no studies have shown how one converted to the other as life started evolving and this may be because both arose at the same time on Earth.

It was generally assumed that RNA was the basis for the first life on Earth because it’s simpler and more versatile compared to DNA.

“These new findings suggest that it may not be reasonable for chemists to be so heavily guided by the RNA World hypothesis in investigating the origins of life on Earth,” said Ramanarayanan Krishnamurthy, a co-principal investigator for the study.

The researchers built on a 2017 study that identified a compound that could have helped RNA and DNA blocks form chains.

The team focused on a compound called thiouridine which could have been an early precursor to the building blocks of life.

In just a few chemical reactions the researchers were able to convert thiouridine into deoxyadenosine, which is a building block of DNA.

“There is the beginning of a realization in the field that RNA and DNA could have been mixed together initially but later separated according to the things they do best,” Krishnamurthy says.

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By Kay Vandette, Earth.com Staff Writer