Scientists of the Nagoya University in Japan have shown that molecules similar to DNA, not RNA, could serve as predecessors of living organisms on Earth. This is reported in an article published in the journal Nature Communications. Briefly about scientific work is described in a press release on MedicalXpress.
Researchers believe that before the appearance of the first living cell, there was a world of pre-RNA based on xenonucleic acids (XNA). In contrast to RNA chains, the replication and assembly of the XNA does not require enzymes. The xenonucleic acid chains are fairly stable to carry genetic information. They are also able to bind to proteins and enjoy enzymatic functions like ribosimams (so scientists call ribonucleic acids capable of catalyze biochemical reactions).
scientists were synthesized by aliphatic fragments (not having cycles) of L-threoninol nucleic acid (L-ATNA), which is believed to existed before the appearance of RNA. They also made a longer chain of L-ATNA, which was complementary of the original sequence of fragments, just as two complementary to each other DNA chains create a double helix.
In a test tube under controlled conditions, shorter fragments of L-ATNA were collected together and bind to each other on a longer L-threoninol chain. This happened in the presence of a compound called N-cyanoimidazole, and a metal ion, such as a manganese, both of which were most likely attended on early earth.
Fragments L-ATNA could also be born with DNA and RNA. This suggests that the genetic code can be transferred from DNA and RNA to L-ATNA and back.
According to scientists, the results of the study will help future developments on creating artificial life and high-functional biotechnological tools consisting of acyclic XNA.