Scientists investigating the evolution of the virus that causes Covid19 say that its mutation seems to be directed by human proteins that degrade it, but natural selection of the virus enables it to bounce back. The findings could help in the design of vaccines against the virus.

All organisms mutate. You were for example born with between 10 and 100 new mutations in your DNA. Mutation is usually a random process often owing to mistakes made when DNA is copied. Recent work from researchers at the Universities of Bath and Edinburgh, suggests that in the case of SARS-CoV-2, mutation may well not be a random process and that instead humans are mutating it, as part of a defence mechanism to degrade the virus.

The team looked at over 15,000 virus genomes from all of the sequencing efforts around the world and identified over 6000 mutations. They looked at how much each of the four letters that make up the virus’ genetic code (A, C, U and G) were mutating and discovered that the virus had a very high rate of mutations generating U residues.

Senior author Professor Laurence Hurst, Director of the Milner Centre for Evolution at the University of Bath, said: “I have looked at mutational profiles for many organisms and they all show some sort of bias, but I’ve never seen one as strong and strange as this.”

In particular they found that mutation very commonly generated UU neighbouring pairs, mutating from the original sequence of CU and UC. They noted this is a fingerprint of the mutational profile of a human protein, called APOBEC, that can mutate viruses. Professor Hurst commented: “It looks like mutation isn’t random, but instead we are attacking the virus by mutating it.”

Image Credit:  Amanda Scott/Envato

Thanks to Heinz V. Hoenen.  Follow him on twitter: @HeinzVHoenen

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