“These findings strongly support an urgent need for further immediate, comprehensive studies.”
Coronavirus has mutated into a “more aggressive disease,” say scientists
Virus has evolved into two major lineages and it is possible to be infected with both, a new study shows
By Sarah Knapton
Coronavirus has mutated into two strains, one which appears to be far more aggressive, scientists have said, in a discovery which could hinder attempts to develop a vaccine.
Researchers at Peking University’s School of Life Sciences and the Institut Pasteur of Shanghai, discovered the virus has evolved into two major lineages – dubbed ‘L’ and ‘S’ types.
The older ‘S-type’ appears to be milder and less infectious, while the ‘L-type’ which emerged later, spreads quickly and currently accounts for around 70 per cent of cases.
Genetic analysis of a man in the US who tested positive on January 21, also showed it is possible to be infected with both types.
The finding comes just days after government health experts warned that the virus could hit Britain in ‘multiple waves’, and led to fears that some vaccines might not work on mutated strains… Read more.
On the origin – and continuing evolution – of SARS-CoV-2 [Coronavirus]
Mar 3, 2020
National Science Review – The SARS-CoV-2 epidemic started in late December 2019 in Wuhan, China, and has since impacted a large portion of China and raised major global concern.
Herein, we investigated the extent of molecular divergence between SARS-CoV-2 and other related coronaviruses.
Although we found only 4% variability in genomic nucleotides between SARS-CoV-2 and a bat SARS-related coronavirus (SARSr-CoV; RaTG13), the difference at neutral sites was 17%, suggesting the divergence between the two viruses is much larger than previously estimated.
Our results suggest that the development of new variations in functional sites in the receptor-binding domain (RBD) of the spike seen in SARS-CoV-2 and viruses from pangolin SARSr-CoVs are likely caused by mutations and natural selection besides recombination.
Population genetic analyses of 103 SARS-CoV-2 genomes indicated that these viruses evolved into two major types (designated L and S), that are well defined by two different SNPs that show nearly complete linkage across the viral strains sequenced to date.
Although the L type (∼70%) is more prevalent than the S type (∼30%), the S type was found to be the ancestral version.
Whereas the L type was more prevalent in the early stages of the outbreak in Wuhan, the frequency of the L type decreased after early January 2020.
Human intervention may have placed more severe selective pressure on the L type, which might be more aggressive and spread more quickly.
On the other hand, the S type, which is evolutionarily older and less aggressive, might have increased in relative frequency due to relatively weaker selective pressure.
These findings strongly support an urgent need for further immediate, comprehensive studies that combine genomic data, epidemiological data, and chart records of the clinical symptoms of patients with coronavirus disease 2019 (COVID-19). Source.