Genome Sequencing
Context:
- The Genome India Project’s mission to sequence 10,000 Indian human genomes and create a database is around two-thirds complete, according to a recent report from the Department of Biotechnology. Three thousand of the approximately 7,000 sequenced Indian genomes are available to the general scientific community.
DNA synthesis definition:
- A genome is the entire collection of genetic instructions included in an organism’s DNA. Sequencing uses four nucleotide bases: adenine (A), cytosine (C), guanine (G), and thymine (T).
- The human genome is made up of more than 3 billion of these genetic letters. The entire genome cannot be sequenced all at once because existing DNA sequencing methods can only handle small pieces of DNA at a time.
- Human genomes are constituted of DNA (deoxyribonucleic acid), whereas viral genomes can be built of either DNA or RNA (ribonucleic acid). Coronavirus is created using RNA. Each organism has a unique genetic sequence.
- Genome sequencing is a technique for examining genetic information stored in DNA or RNA.
History:
- In 1990, a group of scientists began deciphering the entire human genome under the aegis of the Human Genome Project. The Project made the most recent iteration of the full human genome, with a 0.3% error margin, public in 2023. This shows how genome sequencing has developed to the point that large-scale sequencers can process thousands of samples at once.
Approaches:
- There are two methods for dividing the genome into smaller bits and piecing it back together.
- The “clone-by-clone” technique involves first slicing the genome into clones that are each around 150,000 base pairs (bp) in size.
- The “whole-genome shotgun” method involves cutting the genome into manageable pieces, sequencing the pieces, and then reassembling the pieces to obtain the sequence of the entire genome.
- Whole-genome sequencing is now possible thanks to the Human Genome Project, making it simpler to read an individual’s genome and spot differences from the genomes of other individuals.
Applications for sequencing:
- Genome sequencing has been used to evaluate cancer, risk factors for illnesses, and rare genetic diseases from a genetics-based perspective rather than as diseases of specific organs.
- Understanding the Virus: Understanding how specific mutations affect a virus’s contagiousness is the aim of genome sequencing. Some changes provide an explanation for the virus’ resistance to antibodies or immunological escape, which has consequences for immunisations.
- Investigating Efficacy: It is important to find out whether the vaccines developed so far are effective against these mutant strains of the virus and whether they can prevent transmission and reinfection.
- Tracing Mutations: Sequencing the viral strain genomes is significant from a “know thy enemy” standpoint since it makes it easier to trace the mutations.
- Developing vaccines: Knowledge collected through critical research is used to develop vaccines for diseases that are currently prevalent as well as those that may emerge in the future.
- Significant data and inferences can be made from the genome sequencing of individuals who tested positive for COVID.
Perform during a pandemic:
- The coronavirus genome was initially sequenced in Wuhan, China, in January 2020, at the start of the pandemic. Virologists then began examining the sequence in an effort to understand how to combat the virus, keep track of the intensity and spread of the evolving varieties, and create a vaccine.
- In order to enable an efficient reaction against COVID-19, researchers kept an eye on emerging variants and conducted more research on their capacity to transmit disease, evade the immune system, and cause severe illness. Genomic sequencing was one of the first phases in this critical procedure. In this case, genome sequencing aimed to understand how certain mutations affected the virus’s contagiousness.
Indian achievements:
- India has built the Indian SARS-COV-2 Genomics Consortia (INSACOG), a sequencing framework. Coronavirus samples from patients were given to this network of laboratories for analysis in order to look for any mutations that were known to have boosted transmission overseas.
- The “Genome India” gene-mapping project has been given government approval in order to reflect the Indian “reference genome” in a grid and better comprehend the various illnesses and characteristics that impact the diverse Indian population.
Moving forward:
- The quantity of laboratories needs to be increased in order to advance the investigation at the required rate. The Union Health Minister has announced the opening of 17 more laboratories for the same reason.
- The analysis of the connections between virus variants and epidemiological waves (outbreaks, super-spreader events), which will be aided by the information acquired from the virus’ genome sequencing, will also benefit from the information.
