Artificial enzymes suggest life doesn't need DNA or RNA

Researchers have developed artificial enzymes from genetic material that does not exist in nature, called XNA, an advance that hints at the possibility that life could evolve without DNA or RNA.
DNA or deoxyribonucleic acid and ribonucleic acid or RNA are two self-replicating molecules considered indispensable for life on Earth.
"Our work with XNA shows that there's no fundamental imperative for RNA and DNA to be prerequisites for life," said Philipp Holliger of the Laboratory of Molecular Biology in Cambridge, UK.
XNA or xeno nucleic acid created by Holliger's team contains the same bases - adenine, thymine, guanine, cytosine and uracil - on which DNA and RNA rely for coding hereditary information, 'New Scientist' reported.

In DNA and RNA, the sugars are deoxyribose and ribose, respectively. Holliger made new types of genetic material by replacing these with different sugars or other molecules.
In the new study, researchers showed that XNAs can also serve as enzymes - indispensable catalysts for speeding up chemical reactions vital for life.

One of the first steps towards life on Earth is thought to be the evolution of RNA into self-copying enzymes.
The XNA enzymes can't yet copy themselves but they can cut and paste RNA, just like natural enzymes do, and even paste together fragments of XNA.
Holliger said that RNA and DNA may have come to dominate Earth by chance, simply because they were the best evolutionary materials to hand.

"You could speculate that on other planets, XNAs would dominate instead," he said.