Most extensive genetic sequencing of the new coronavirus to date reveals it has undergone few mutations – which may facilitate the development of treatments for Covid-19.
Researchers at the University of Bologna, in Italy, identified the existence of at least six strains of the new coronavirus, which causes Covid-19.
The study took into account 48,635 genomes that were isolated and evaluated by scientists from different countries.
The results were published on July 22 in the journal Frontiers in Microbiology and, according to the researchers, is the most extensive Sars-CoV-2 sequencing study to date.
Scientists also found that the microorganisms have little variability between them: there are about seven mutations per sample.
“The SARS-CoV-2 coronavirus is presumably already optimized to affect human beings, and this explains its low evolutionary change,” explained Federico Giorgi, one of the researchers, in a statement. “This means that the treatments we are developing, including a vaccine, might be effective against all the virus strains.”
There are currently six strains of Sars-CoV-2, according to the research. The original is the L strain, which appeared in Wuhan, China, in December 2019. Its first mutation (S) appeared in early 2020.
In mid-January, two other strains of the virus were detected, V and G. The latter is the most widespread: it became two types, GR and GH, both detected in February.
“Strain G and its related strains GR and GH are by far the most widespread, representing 74% of all gene sequences we analyzed,” Giorgi said. “They present four mutations, two of which are able to change the sequence of the RNA polymerase and Spike proteins of the virus. This characteristic probably facilitates the spread of the virus.”
Looking at the “coronavirus map”, we can see that the G and GR strains are the most frequent in Italy and Europe in general.
According to available data, GH hardly appears on Italian soil, but it is the main strain circulating in France and Germany.
In North America, on the other hand, the most widespread strain is GH; and in South America GR is found more frequently.
In Asia, where the L strain appeared, the spread of G, GH, and GR is increasing. These strains arrived on the Asian continent only in early March, more than a month after their spread in Europe.
Globally, strains G, GH, and GR are increasing, while L and V are gradually disappearing. The S strain, in turn, can still be found in specific regions in the United States and Spain.
Scientists also found rare genetic mutations in some strains, but they appeared in less than 1% of the analyzed material.
“However, it is fundamental that we study and analyze them so that we can identify their function and monitor their spread,” Giorgi said. “All countries should contribute to the cause by giving access to data about the virus genome sequences.”