After analyzing the genome of the coronavirus, experts discovered why the British, Brazilian and South African variants are more dangerous
Months after the statement Coronavirus disease, At the beginning of 2020, scientists Viral genome, This SARS-CoV-2, But many protein-coding genes are still unknown. Now, through comparative genomics research, the most accurate and complete genetic map can be generated. virus.
The research was done by researchers at the Massachusetts Institute of Technology (MIT) and was published in the journal Nature Communications on Tuesday. The study has confirmed several protein-coding genes and found that other proteins proposed as genes did not code for any proteins.
In the second part of the study, the research team also studied 2,000 mutations in SARS-CoV-2 From the beginning of the pandemic it allowed them to assess the importance of these mutations and their ability to evade the immune system or become more contagious.
The SARS-CoV-2 genome has nearly 30,000 RNA bases. Several regions are known to encode protein genes, while other regions are suspected but not yet clearly classified.
To determine which parts of the SARS-CoV-2 genome actually contain genes, the researchers turned to Comparative genomics, And then compared SARS-CoV-2 (a virus called Sarbecovirus that infects bats) with SARS-CoV (which caused the SARS outbreak in 2003) and 42 bat sarbecoviruses.
Therefore, they identified six protein-coding genes in the SARS-CoV-2 genome and five protein-coding genes that have been established in all coronaviruses.
They also determined that the region encoding the gene called ORF3a also encodes another gene, ORF3c, which has RNA bases that overlap with ORF3a but is in a different reading frame, which is rare in large genomes, but in many genomes Very common in virus Moreover, for SARS-CoV-2, its function is unclear.
The researchers also showed that the five other possible gene regions that have been proposed do not code for functional proteins and exclude other regions that are still to be discovered.
In addition, the authors found that many previous works not only used the wrong gene set, but sometimes used contradictory names. Therefore, in a recent parallel article published in the journal Virology, they proposed to name the gene Suggestions. SARS-CoV-2.
In this study, the researchers also analyzed more than 1,800 mutations that occurred in SARS-CoV-2 and found that in most cases, genes that evolved rapidly before the pandemic continued, while genes that tended to evolve slowly But it continues to be popular. This trend has been maintained.
They also studied the mutations produced in worrying variants, such as the British, Brazilian and South African strains, and found that many of the mutations that make these variants more dangerous are present in the spike protein, which helps the virus to spread quickly. And spread. Bypass the immune system.
However, each of these variants has “over 20 mutations, so it is important to know which of them can do and which cannot,” the lead author of the study, MIT researcher Irwin Jungreis Say.
For the author, these data can help other scientists focus on the mutations that seem to have the greatest impact on the infectivity of the virus.