D614G MUTATION

Subject: Science & tech

Context: While novel coronavirus is undergoing many mutations, one particular mutation called D614G, according to a study, has become the dominant variant

Concept:

• All viruses mutate to adapt to the barriers that humans put up. RNA viruses such as SARS-CoV-2 mutate slowly as they require a host (human cell) in order to replicate.
• Until now, 12,000 mutations have been documented in over 3.2 crore cases globally. One mutation has been found the most widespread.
• It was first noticed in China and Germany, but gained attention when it cropped up in several cases across Europe, and eventually in the US, Canada, Australia and India.
• In this mutation, glycine (G) replaces aspartic acid (D) in the 614th position in the amino acid. Hence the mutation came to be referred as ‘D614G’.

What Are Mutations ?

• The DNA sequence is specific to each organism. It can sometimes undergo changes in its base-pairs sequence. It is termed as a mutation. A mutation may lead to changes in proteins translated by the DNA. Usually, the cells can recognize any damage caused by mutation and repair it before it becomes permanent.

What makes this mutation unlike others?

• To understand this, we must understand how SARS-CoV-2 enters a human cell. The amino acids where mutation occurs are located in the spike protein of the virus. The spike proteins binds with the ACE2 receptor on the human cell and gains entry.
• Scientist in CSIR-Institute of Genomics and Integrative Biology, explained, “It is the peptides in the spike protein that lock with the ACE2 receptor. In D614G mutation, two of the three peptides open up, making chances of entry into human cell higher.
• Because its nature allows a better chance of entering a host cell than other mutated strains, D614G has a higher rate of transmission.
• GISAID, a global virus database that has documented all circulating strains of SARS-CoV2, shows that the mutated strain gained prominence from March onwards in Europe.