Odd molecular hoops dispel 'junk DNA' myth

Nicolle Rager Fuller / NSF

An artist's conception shows an RNA molecule, which may have served as an early form of life on Earth.

By Charles ChoiLiveScience

The human genome can generate molecular hoops similar in makeup to DNA that could potently interfere with genetic activity, researchers say.

These findings reveal there are secrets within the genomes of humans and other animals that scientists are still uncovering, and the old belief that life has useless junk DNA is more false than ever, scientists added.

Discovering more about circular versions of RNA (a molecule similar to DNA that can carry genetic information) could also lead to new ways of fighting diseases such as diabetes, brain tumors and Parkinson's disease, investigators added.

The human genome the blueprint for human life is made of DNA. From the genome, intermediate molecules known as RNA are created that help manufacture key biomolecules such as proteins, which then carry out cellular processes.

After international teams of researchers completely sequenced the human genome, they found about 95 percent of it unexpectedly did not code for proteins. Since this noncoding DNA initially seemed to have no known biological function, some scientists referred to it as junk DNA. [Unraveling the Human Genome: 6 Molecular Milestones]

However, over time, researchers have discovered this noncoding DNA can serve a wide variety of vital purposes. For instance, noncoding DNA can give rise to snippets of RNA known as micro-RNA that can suppress the so-called messenger RNA that normally helps manufacture proteins. This micro-RNA serves a key role in controlling genetic activity, and scientists are developing therapies based on micro-RNA to dampen harmful, malfunctioning genes.

Now researchers find the genomes of humans and other animals can generate circular RNA, highly stable rings that can sponge up micro-RNA, apparently keeping them from interfering with genetic activity if necessary.

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Odd molecular hoops dispel 'junk DNA' myth