But the biggest surprise was that during the DNA reaction the virus had a polymerase enzyme dedicated to binding the Z base to T. “It was like a fairy tale,” said Malier, who hoped to find such a polymerase. “Our wildest dreams came true.”

This is because while scientists have found other examples of bacteriophage nucleotide substitutes, this is “the first polymerase that has actually been shown to selectively exclude a canonical nucleotide,” neither England nor England studied nickel-based biosynthesis. Said Peter Weigel, a researcher at Bylabs. The system was developed to allow “re-rog programming” – which provides new insights into how polymerase works, and how they can be engineered, Romsberg said.

Z and other modified DNA bases appear to have evolved to protect against viruses, with which bacteria degrade foreign genetic material. According to Romansburg, the perpetual weapon race between bacteriophages and their host cells provides sufficient selection pressure to possibly affect something as “cultured” as DNA. “Right now, everyone thinks the changes are just protecting DNA.” “People make it almost trivial.”

But something more could be at work: Z’s triple bond, for example, could increase the stability and rigidity of DNA, and perhaps affect some of its other physical properties. Those changes can have benefits in addition to hiding from bacterial defenses and make such changes more widely noticeable.

After all, no one really knows how many viruses have played with their DNA in this way. “Default [genome sequencing] Methods for finding biodiversity in nature will fail to find this, “said Steven Banner, a chemist at the Foundation for Applied Molecular Evolution in Florida, who synthesized several synthetic base pairs,” because we’re looking for a common assumption. Biochemistry that is not present. “

These types of neglected substitutes can change even more than viruses. “Maybe we missed some of this in the world of bacteria, right?” Said Chuan Hai, a chemical biologist at the University of Chicago.

Artificial biology has (again) shown that this is possible. Over the years, Marlier’s team has been evolving E. coli Which uses a modified base instead of T nucleotides. The University of Illinois, Urbana-Champion chemist and some of the leaders of the recent Z genome work are trying to get Human Zhao. E. coli And potentially other cells to contain Z like viruses.

Romsburg thinks these findings may raise questions about changes in bacterial DNA that were thought to be epigenetic – that is, changes in nucleotides after DNA synthesis, in general, to influence gene expression. That said, the Z substitute, it shows that the things you might be thinking may not be epigenetic. “

“I think people need to look under the rocks to understand,” he added. “Surprise from there.”

Carol Cleland, a science philosopher at Boulder, University of Colorado, said there are plenty of surprising places, even in less-studied places. “Is there any other stuff we’re not able to identify?”

Marlier wonders, for example, if scientists could stumble upon more than one type of fundamental change in the same genome one day. Or maybe they’ll get a change in the molecular backbone of DNA, in which case “it won’t be DNA anymore,” he said. “It will be something else.”

Freeland said we should “stop taking components of nuclear biology because we know them.” “Purely because our instrumentation has gotten better and we’ve felt harder, everything we believed and was universal is moving.”

Original story Reprinted with permission from Quanta Magazine, An editorial independent publication Simmons Foundation The aim is to enhance public understanding of science by covering mathematical research developments and trends and physical and life sciences.


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