Innovations in Biotechnology and Medical Sciences

What is Genome Sequencing?

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Genome sequencing, APOBEC3 protein

Mains level : NA

Researchers from across the world have made available over 650 complete genome sequences of monkeypox isolates to date in public domain databases including GISAID and GenBank.

What is Genome Sequencing?

  • Genome sequence is the unique code of genetic material of any organism, and determines the characteristic of any organism.
  • Whole genome sequencing is the process of determining the complete DNA sequence of an organism’s genome at a single time.
  • The gene composition of novel coronavirus, for instance, is different from that of the influenza virus. Every organism has a unique genome sequence.
  • Laboratories in various countries have been isolating and sharing the genome sequences of the virus on an international platform.

Why are so many genome sequences being isolated?

  • When viruses multiply, or reproduce, there is a copying mechanism that transfers the gene information to the next generation.
  • However, no copying mechanism is perfect. When the virus multiplies, there will be small changes, which are called mutations.
  • These mutations accumulate over time, and after prolonged periods, are responsible for evolution into new organisms.
  • Within a single reproduction, the changes are extremely minor. More than 95 per cent of the gene structure remains the same.

How does it help scientists?

  • However, the small changes that occur are crucial to understanding the nature and behaviour of the organism.
  • In this case, for example, the small changes could provide scientists with information about the origin, transmission, and impact of the virus on the patient.
  • It could also hold clues to the differing effects the virus could have on patients with different health parameters.

Accelerated evolution of Monkeypox

  • The monkeypox virus has a DNA genome of around 2,00,000 base pairs, roughly six times larger than that of SARS-CoV-2.
  • Like other viruses, the monkeypox virus evolves by the accumulation of genetic errors, or mutations, in its genome when it replicates inside a host.
  • Being a DNA virus, the monkeypox virus like other poxviruses was believed to have a small rate of accumulating genetic changes compared to viruses with an RNA genome like SARS-CoV-2, which have a much larger rate of mutations.
  • For poxviruses, this rate is estimated to be as low as a couple of genetic changes every year.
  • A recent study, however, revealed that the observed rate of genetic changes in the virus was higher than expected — average of around 50 genetic changes.

Key findings

Ans. APOBEC3 protein

  • The study also suggests that several mutations that have been identified in the new sequences of the monkeypox virus.
  • This may have emerged due to interaction between the virus genome and an important family of proteins coded by the human genome known as the Apolipoprotein B Editing Complex (or APOBEC3).
  • These proteins offer protection against certain viral infections by editing the genome sequence of the virus while it replicates in the cell.
  • Some researchers suggest that many of the genetic mutations in the monkeypox genomes from the current outbreak are relics of the effect of APOBEC3.

Conclusion

  • Genomic surveillance of pathogens provides interesting insights by following a molecular approach for contact tracing and understanding the transmission of the virus across the world.
  • As cases of monkeypox continue to rise, it is therefore important to strengthen the genomic surveillance for the monkeypox virus.
  • Since data from the present outbreak suggest a sustained human-to-human transmission, continuous genomic surveillance is important to understand the evolution and adaptation of the virus, apart from providing useful data to epidemiologists.
  • With COVID-19 continuing unabated and monkeypox around the corner, the time has never been better, and the need never more acute, to build a sustainable system for genomic surveillance in India.

 

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