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Nagoya University researchers have established that DNA-like molecules could be the origin of life. The scientist published their findings in the Nature Communications journal in an article titled, “Nonenzymatic polymerase-like template-directed synthesis of acyclic L-threonninol nucleic acid.”

XNAs are responsible for the origin of life. 

Besides findings suggesting how life started, the articles have a new model applicable in biotech applications and artificial life development.  One of the study authors and biomolecular engineers at Nagoya University, Keiji Murayama, said that RNA is usually assumed to be a stage in life’s evolution. However, the “pre-RNA universe” may have been founded on molecules known as Xeno nucleic acids (XNAs).  Murayama said that, unlike RNA, XNA replication is unlikely to have necessitated the use of enzymes. He said they managed to synthesize an XNA without using enzymes, indicating that the XNA world may have existed before the RNA world.

Like its alleged forerunners, an XNA is made up of nucleotide chains but with a distinct sugar backbone. The simple molecules also carry gene sequences in a stable form since the human body is incapable of further degrading them. Similar studies have found that XNAs with specific sequences can act as enzymes by attaching to proteins. As a result, XNAs have a lot of potential in the fields of molecular medicine, synthetic genetics, and biotechnology.

Scientists created L-aTNA fragments. 

Murayama and co-scientists wanted to establish if conditions on early Earth could have contributed to XNA chain development. As a result, they created acyclic (non-circular) L-threoninol nucleic acid (L-aTNA) fragments, a molecule that predates RNA. Equally, they created a longer L-aTNA with a nucleobase sequence matching the fragment sequences, similar to how DNA strands complement one another.

Muraya said, “To the best of our knowledge, this is the first demonstration of template-driven, enzyme-free extension of acyclic XNA from a random fragment pool, generating phosphodiester bonding.” 

The scientists have also shown that L-aTNA fragment scan interlink RNA and DNA templates suggesting that genetic information can be transferred from DNA and RNA to L-aTNA.