George Romero's The Crazies
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What even is this freaky virus with DNA no one ever heard of?

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Feb 16, 2020, 3:41 PM EST (Updated)

This isn’t an alien conspiracy theory, but there is still something crawling on Earth whose DNA is completely alien to us.

Yaravirus has no genes anyone has ever heard of. Unknown viruses are creeping everywhere, but when scientists discover one, its genetic makeup can usually be figured out somehow. What made this one break the internet is its mysterious DNA. It could mean that we might not be so familiar with the life forms on our own planet as we may think we are. While this might be the last thing you want to hear during the coronavirus scare, this microbe is only a threat if you’re an amoeba.

“Contrary to what is observed in other isolated viruses of amoeba, Yaravirus is not represented by a … complex genome, but at the same time carries an important number of previously undescribed genes,” said virologist Jônatas Abrahão and colleagues in a study recently posted on bioRxiv.

At least you won’t be needing a hazmat suit like in George Romero’s bioterrorism thriller The Crazies (above).

Strange new viruses emerge all the time, but it’s not every day you find one that might as well have jumped out of science fiction. It was accidentally discovered in a Brazilian lagoon during a hunt for giant viruses, which may sound like the start of some retro B-horror movie with a title like Attack of the Giant Viruses (which never actually existed). Giant viruses are really just viruses the size of bacteria. The average bacterium is about 20 times larger than the average virus, and the largest virus doesn’t get anywhere near the smallest bacterium. Some scientists believe giant viruses are living relics of ancient cells that evolved into parasites.

The one thing about Yaravirus that isn’t so creepy is that it was named after a goddess in the local Tupi-Guarani mythology—Yara, the mother of waters.

It got even more confusing when Abrahão’s team went under the microscope. They saw that some Yaravirus genes looked like those commonly found in giant viruses, since most viruses that infect amoeba tend to share certain features, but they weren’t a match. This may or may not mean there is some sort of distant relation between Yaravirus and giant viruses. Whether they are even related at all remains hazy. Virus DNA is classified by the proteins that make up the capsid (shell) of that virus, and while the sequences of virus genes are often weird, the thing with Yaravirus is that no individual protein in its capsid resembled any that were already known.

Forget sequences and genomes when you can’t even identify individual genes. The researchers were unable to find any viral genome that was remotely close after searching 8,535 metagenomes (all the DNA extracted and sequenced from a sample, then saved to a database) from all over the planet. Only six of its genes have even distant relatives. 68 of those genes, which make up over 90%, were completely unknown until now. How Yaravirus lives and survives remains a mystery.

Just be glad that, in the wake of another new virus discovery, you’re not an amoeba.

(via Science Magazine/bioRxiv)

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