Exclusive: Two variants have merged into heavily mutated coronavirus
The UK and California variants of coronavirus appear to have combined into a heavily mutated hybrid, sparking concern 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 have combined their genomes to form a heavily mutated hybrid version of the virus. The “recombination” event was discovered in a virus sample in California, provoking warnings that we may be poised to enter a new phase of the pandemic.
The hybrid virus is the result of recombination of the highly transmissible B.1.1.7 variant discovered in the UK and the B.1.429 variant that originated in California and which 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 at the Los Alamos National Laboratory in New Mexico, who told a meeting organised by the New York Academy of Sciences on 2 February that she had seen “pretty clear” evidence of it in her database of US viral genomes.
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 hadn’t seen any evidence of recombination, even though it has long been expected as it is common in coronaviruses.
Unlike regular mutation, where changes accumulate one at a time, which is how variants such as B.1.1.7 arose, recombination can bring together multiple mutations in one go. Most of the time, these don’t confer any advantage to the virus, but occasionally they do.
Recombination can be of major evolutionary importance, according to François Balloux at University College London. It is considered by many to be how SARS-CoV-2 originated.
Recombination could lead to the emergence of new and even more dangerous variants, although it isn’t yet clear how much of a threat this first recombination event might pose.