Anyone curious to see evolution playing out in real time need look no further than NextStrain.org, a website that depicts the ever-sprouting family trees of different pathogens residing in the human population.
Maintained by a collective of computational biologists, NextStrain is currently displaying more than 3,500 genetically distinct branches of SARS-CoV-2, the virus that causes COVID-19. Those are just a selection of all the variations that have been seen. More are showing up all the time, thanks to the immense opportunity for diversification that the virus has gained by infecting about 80 million people this year.
Mostly, these dissimilarities lead to identical behaviour in the virus. Like fingerprints, their genetic codes are useful for identification and for tracing the history of various outbreaks. But the disease they cause is the same.
That is not the case for a new variant, first spotted in Britain and now known to be in Canada. Based on epidemiology and preliminary lab reports, the variant may be shifting the character of COVID-19 enough to make a difference in how the disease spreads and who catches it.
This has caused concern not only because of the potential for the pandemic to accelerate, but because a changing virus may become harder for standard COVID-19 tests to spot and for newly approved vaccines to defend against.