Clade A3i


  • Recently, scientists from the Centre for Cellular and Molecular Biologyand the Institute of Genomics and Integrative Biology of the Council of Scientific and Industrial Research (CSIR) laboratories have identified a coronavirus type (A3i) that may be the second most prevalent in India and may comprise 3.5% of the genomes globally.


  • The scientists analysed 213 genomes and found that 62% of them were A2a,making it the most dominant coronavirus clade in India.
  • This particular genetic difference, named ‘Clade I/A3i’, 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. In layman terms, a clade can be understood as a strain of the virus.
  • The newly identified A3i or Clade I/A3i comprised 41%, making it the second most common coronavirus type in India.
  • 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 US, and Europe via air travelers.
  • With the new clade, there are 11 SARS-CoV-2 types identified globally with at least six of them identified in India.
  • The A2i type, once it took root, became the dominant clade in Telangana and also Tamil Nadu, Maharashtra, and Delhi.

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