The UK and California coronavirus variants appear to have combined into a highly mutant hybrid, which has raised concerns that we may be entering a new phase of the covid-19 pandemic.
Two variants of the SARS-CoV-2 coronavirus that causes Covid-19 combined their genomes to form a heavily mutated hybrid version of the virus. The “recombination” event was discovered in a sample of viruses in California, prompting warnings that we may be ready to enter a new phase of the pandemic.
Recombinant From A Highly Transmissible Strain Resistant To Some Antibodies
The hybrid virus is the result of the recombination of the highly transmissible variant B.1.1.7 discovered in the United Kingdom and variant B.1.429 that originated in California and that may be responsible for a recent wave of cases in Los Angeles because it carries a mutation making it resistant to some antibodies.
The recombinant was discovered by Bette Korber in Los Alamos National Laboratory, in New Mexico, who said at a meeting organized by New York Academy of Sciences on February 2 she had seen “fairly clear” evidence of him in her United States viral genome database.
The first recombinant
If confirmed, the recombinant would be the first to be detected in this pandemic. In December and January, two research groups independently reported that they did not had seen no evidence of recombination, although it was long expected, since it is common in coronavirus.
Unlike regular mutation, where changes accumulate one at a time, which is how variants like B.1.1.7 came about, recombination can bring together several mutations at once. Most of the time, this does not give any advantage to the virus, but occasionally it does.
Recombination can be of great evolutionary importance, according to François Balloux, from University College London. It is considered by many to be the origin of SARS-CoV-2.
Recombination can lead to the emergence of new and even more dangerous variants, although it is not yet clear how much of a threat this first recombination event can represent.
Korber saw only a single recombinant genome among thousands of sequences and it is unclear whether the virus is being transmitted from person to person or just isolated.
The recombination usually occurs in coronavirus because the enzyme that replicates your genome is prone to slide off the RNA strand you're copying and then reunite where you left off. If a host cell contains two different coronavirus genomes, the enzyme can jump from one to the other repeatedly, combining different elements from each genome to create a hybrid virus.
O The recent emergence of multiple variants of the new coronavirus may have created the raw material for recombination because people can be infected with two different variants at the same time.
"We may be getting to the point where this is happening at appreciable rates," says Sergei Pond, from Temple University, Pennsylvania, who keeps an eye on recombinants comparing thousands of genome sequences loaded into databases. He says there is still no evidence of widespread recombination, but that "all coronaviruses recombine, so it is a matter of when, not if".
The implications of the discovery are still unclear because very little is known about the biology of the recombinant. However, it carries a mutation of B.1.1.7, called Δ69 / 70, which makes the UK virus more transmissible, and another of B.1.429, called L452R, which can confer resistance to antibodies.
"This type of event could allow the virus to have coupled a more infectious virus to a more resistant virus," said Korber at the New York meeting.
Lucy van Dorp, from University College London, says she hadn't heard of the recombinant yet, but "I wouldn't be too surprised if some cases started to be detected."
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Translated by Cláudio Souza on March 19 (better late than never) from the original in Exclusive: Two variants have merged into heavily mutated coronavirus published on / February 6, 2021by Graham