NEW DELHI: Following a study of genomes of various variants of Covid-19 virus from over 2 lakh samples, scientists have predicted that the persistence of pandemic may lead to the emergence of newer regional strains with improved fitness.
The scientists analysed 200,865 SARS-CoV-2 genome sequences from 155 countries, which had 2.58 million mutations as of late last year as compared to the reference Wuhan strain.
They found about 39% synonymous mutations, mutations that are usually minor and do not change the amino acids while about 51% were non-synonymous mutations, which are mutations that change the amino acids.
Upon comparing the variants predominant in the three new strains, the researchers found four common hotspot mutations, noted scientists attached with the Integrated Cancer Genomics Laboratory, Homi Bhabha National Institute and Institute of Advanced Virology, Kerala.
Their paper “Evolving Insights from SARS-CoV-2 Genome from 200K COVID-19 Patients” says that N501Y was the base mutation in all the three variants, with the South African and Brazilian strains showing additional E484K mutation in the spike protein.
Neither of these two mutations however were seen in the Indian samples, and only two out of 3,361 samples showed S477N (characteristic of European mutations) mutation.
The scientists however said that it is unknown if the absence of these mutations, which have increased binding affinity to the human angiotensin-converting enzyme 2 (ACE2) receptor, could account for the lower transmission in India compared to the UK, Brazil, and South Africa.
Even a modest increase in infectivity rate of a regional variant or a reduction in vaccine efficacy or increased transmission would require immediate stringent measures to be put in place to contain the spread of the strain.
In India, following concerns of spread of UK variants of SARS CoV 2, the national task force on Covid had suggested doing genome sequencing of 5% of all Covid cases nationwide, however it is not yet clear whether this exercise has kicked off.
India carried out far less gene mapping compared to UK and US till last month.