Context: Amid Covid-19, Scientists at multiple CSIR laboratories have identified a type of coronavirus that may be the second most prevalent in India, and may comprise 3.5% of the genomes globally.
Key Findings

• The scientists analysed 213 genomes and found that 62% of them were A2a, making it the most dominant coronavirus clade in India.
• Clade: The coronavirus type or clade, is a cluster of SARS-CoV-2 viruses that share evolutionary similarities and are grouped together based on characteristic mutations or similarities in parts of their genomes. In layman terms, a clade can be understood as a strain of the virus.

About A3i trait

• It was found in 41 per cent of the genome sequences done on the virus collected from Indian patients.
• Globally, only 3.5 per cent of all the genome sequences done on this virus has this particular trait.
• A ‘clade’ is a taxonomic group of organisms that are classified together on the basis of homologous features that are traced to a common ancestor.
• The researchers, who sequenced 64 genomes (the complete set of genetic material) linked the Clade I/A3i cluster to the predominant SARS-CoV-2 strain circulating in Tamil Nadu, Telangana, Maharashtra, and Delhi.
• The genomes isolated from India were classified under five clusters are Clades A2a, A3, A3i, B, and B4.
• According to scientific analysis, the A3i clade mutates slowly compared to the A2a which is often disadvantageous for the virus.
• So far, there is no evidence of whether A3i is more virulent (extremely severe or harmful in its effects) and linked to more deaths.
• A3i is the predominant strain circulating in Tamil Nadu, Telangana, Maharashtra and Delhi.

Significance of the Classification:

• Such classifications are useful in establishing whether certain strains are particularly virulent, spread more easily, how they are likely to evolve over time and whether some could be less vulnerable to certain kinds of vaccines.
• With the new clade, there are now 11 SARS-CoV-2 types identified globally with at least six of them identified in India.
• Previous studies have shown that while type O was the first ancestral family of the virus identified from China, it’s the A2a type, which is the most dominant in the world because of a mutation in its genes that allow that coronavirus’ spike to more efficiently infiltrate the lungs.
• The Indian Council of Medical Research (ICMR) has so far maintained that there are three principal variants in India of the SARS-CoV-2 virus: those that came from Wuhan, the USA, and Europe via air travellers.