New Theory on Origin of Life on Earth Questions 'RNA World' Hypothesis

A new study from The Scripps Research Institute (TSRI) has offered a surprising twist of how life began on earth, questioning the likeability of the "RNA World" Hypothesis and proposing that DNA may have also existed when life began.

According to the study published in the journal Angewandte Chemie International Edition, scientists from TSRI said that the RNA World Hypothesis, which states that proteins and DNA originated from RNA molecules, could not be entirely true. They suggested that something could have existed along RNA to help it evolve.

"Why not think of RNA and DNA rising together, rather than trying to convert RNA to DNA by means of some fantastic chemistry at a prebiotic stage?" said Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI and senior author of the new study, via Science Daily.

To recall, scientists have been studying the RNA World Hypothesis for years. The hypothesis claims that self-replicating RNA, which came from multiple chemical reactions, led to the evolution of proteins and enzymes. These byproducts of RNA mark the birth of life on Earth.

At first, scientists thought that DNA and RNA could have merged together to create "heterogeneous" strands that would result to blended "chimeras." However, upon testing, the scientists found that the mixed-up RNA and DNA strands are unstable, especially when the two share the same backbone.

Thus, the researchers came up with an alternate theory, saying that instead of creating "chimeras," RNA and DNA could have evolved at the same time.

This means that apart from RNA, DNA could have also evolved separately in its own homogeneous system. The theory of RNA producing DNA, according to the researchers, could still be possible but it could have occurred after RNA met DNA.