The Omicron variant of the virus that causes Covid-19 likely acquired at least one of its mutations by picking up a snippet of genetic material from another virus — possibly one that causes the common cold — present in the same infected cells, according to researchers.

This genetic sequence does not appear in any earlier versions of the coronavirus, called SARS-CoV-2, but is ubiquitous in many other viruses including those that cause the common cold, and also in the human genome, researchers said.

By inserting this particular snippet into itself, Omicron might be making itself look "more human", which would help it evade attack by the human immune system, said Venky Soundararajan of Cambridge, Massachusetts-based data analytics firm nference, who led the study posted on the website OSF Preprints.

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