Over the past several months, researchers tracking SARS-CoV-2 variants have begun to notice something strange. Instead of one strain becoming dominant, a variety of different variants have started acquiring the same mutations.
As the world tries to return to a semblance of normalcy after enduring a two+ year Coronavirus pandemic, we now have evolutionary signals popping up with the very virus we tried to conquer.
And the virus kept mutating, reports New Atlas, and we were aware of that happening, and our vaccines were adjusted to cover the mutated viruses. However, in September, a new word began to pop up on different social media sites that focused on COVID-19 – Convergence.
Across 2020 experts frequently warned of the potential for this novel coronavirus to mutate, but initially, it remained remarkably unchanged until a trio of variants emerged late in the year.
Suddenly, Alpha, Beta, and Gamma variants popped up. We now had three different lineages, in three different parts of the world. All with relatively similar mutations.
In 2021, the world saw a series of infection waves across the world, each one driven by a new variant. Alpha leading to Delta leading to Omicron. At that time, researchers noticed that each subsequent variant was different from the one that preceded it.
This was not a case of a single strain mutating over time, either. Big evolutionary leaps were being made and new strains were seemingly coming out of nowhere.
Fall and winter surges expected
The phenomenon that caused this strange activity by the virus variants is likely to come into play this fall and through winter, fueled by multiple Omicron spinoffs that look very much alike—both to each other and to older versions of the scourge.
According to Fortune, “they’re expected to be the most immune-evasive, transmissible versions of the virus yet. Their similarity could be a blessing or curse: It could make them easier to fight—or harder to control.”
Dr. Raj Rajnarayanan, assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Ark., told Fortune that a fall COVID wave could be fueled by multiple variants, as many as five, but the differences between them would be minor.
Folks will remember all the talk about the virus’s unique spike protein. It’s the highly identifiable protein that our successful vaccines use to generate protective immune responses.
One part of the spike protein is known as the receptor binding domain (RBD). The RBD sits at the top of the protein and helps the virus to attach itself to certain receptors in human cells – a process essential to infections and replication of the virus.
Our current vaccines, based on the 2020 Wuhan virus spike, are very effective against the current Omicrom variants, only because there have been very few changes in the RBD.
The case for convergent evolution
Convergent evolution is when different organisms independently evolve similar traits. Let’s look at dolphins and sharks for a moment. The two animals look relatively similar, even though sharks are egg-laying fish with the deadly ability to sniff out blood in the water, and dolphins are curious mammals that navigate with built-in sonar.
Those differences aren’t too surprising, considering that the duo’s last common ancestor swam the seas some 290 million years ago. Despite their common ancestor, both animals ended up in similar evolutionary niches: streamlined swimmers with smooth skin and water-slicing fins ideal for chasing down prey.
Interestingly, despite the challenges inherent in Earth’s various habitats, occasionally, different species develop the same solution to the same problem. It all comes down to this – when two organisms share characteristics that they didn’t jointly inherit from a common ancestor — it is called convergent evolution.
Look at the next diagram.
A, Shark (Lamna cornubica), with the long lobe of tail upturned.
B, Ichthyosaur (Ichthyosaurus quadricissus), with fin-like paddles, the long lobe of tail down-turned.
C, Dolphin (Sotalia fluviatilis), with horizontal tail, fin, or fluke.
A new study inBioRxiv, which is yet to be peer-reviewed or published, presents a striking series of data that suggests that a number of new Omicron subvariants are all appearing with similar mutations on the receptor binding domain (RBD).
In an email to New Atlas, the corresponding author of the paper, Yunlong Cao explained that similar mutations across multiple independent variants indicate that SARS-CoV-2 is successfully finding ways to evade our current immunity.
“RBD convergent evolution means that the RBD mutations evolved by the recently emerged SARS-CoV-2 Omicron lineages converge on the same sites (hotspots), including R346, K444, V445, G446, N450, L452, N460, F486, F490, and R493,” Cao explained. “Seeing this convergent evolution pattern would mean that SARS-CoV-2 would evolve immune-evasive mutations much more frequently than before, and the resulting new variants would be much more immune-evasive.”
The question on most researchers’ minds is just where is this convergent evolution going. Will it lead to a COVID-19 “Superbug?” or is Omicron only peaking and will make a “soft landing” in the fall?
