The genetic variation of the novel coronavirus that dominates the world today infects human cells more readily than the original that emerged in China, according to a new study published in the journal Cell on Thursday.
Back on May 6, 2020, Digital Journal reported on a new study led by scientists at Los Alamos National Laboratory that documented their discovery of a new strain of the coronavirus (SARS-CoV-2). Their 33-page report was posted on BioRxiv, a website that researchers use to share their work before it is peer-reviewed.
The mutation identified in the report affects the spikes on the outside of the coronavirus - those infamous thorn-like protuberances - that allow the virus to enter human respiratory cells. The new study was published in the journal Cell on July 2, 2020.
The Los Alamos team, assisted by scientists at Duke University and the University of Sheffield COVID-19 Genomics UK research group analyzed the genome samples. The teams identified 14 mutations. Those mutations occurred among the nearly 30,000 base pairs of RNA that other scientists say make up the coronavirus's genome. reports Science Alert.
The D614G variant
The scientists focused on the D614G mutation which is responsible for the change in the virus' spikes. The Spike D614G amino acid change is caused by an A-to-G nucleotide mutation at position 23,403 in the Wuhan reference strain and was the only site first identified back in March.
Interestingly, using data from the GISAID SARS-CoV-2 sequence database - that is regularly updated - "in March, the D614G form was rarely seen globally. However, between March 1- March 31, it represented 67% of 14,951 sequences; and between April 1- May 18 (the last data point available in our May 29th sample) it represented 78% of 12,194 sequences," according to the report.
The report further noted that "The transition from D614 to G614 occurred asynchronously in different regions throughout the world, beginning in Europe, followed by North America and Oceania, then Asia."
The lab-based research suggests this current mutation is more transmissible between people in the real world compared to the previous iteration, but this hasn't yet been proven.
"I think the data is showing that there is a single mutation that actually makes the virus be able to replicate better, and maybe have high viral loads," Anthony Fauci, the United States's top infectious disease specialist, who wasn't involved in the research, commented to Journal of the American Medical Association.
The one thing that makes this latest study all the more intriguing is that the research teams not only checked for more genetic mutations but conducted experiments involving people, animals, and cells in lab dishes that show the mutated version is more common and that it's more infectious than other versions, according to CNN.
"Our global tracking data show that the G614 variant in Spike has spread faster than D614," theoretical biologist Bette Korber of Los Alamos National Laboratory and colleagues wrote in their report. "We interpret this to mean that the virus is likely to be more infectious," they added. "Interestingly, we did not find evidence of G614 impact on disease severity."
The team's earlier work had been criticized by the editors of Cell and others for not demonstrating whether the mutated form was taking over because it had mutated, or because of random or other reasons.