the story So Far: The Department of Biotechnology (DBT) recently said the exercise to sequence 10,000 Indian human genomes and create a database under the centrally supported Genome India Project is almost two-thirds complete. About 7,000 Indian genomes have already been sequenced, of which 3,000 are available for public access by researchers.
Proponents of the project say it will enable researchers anywhere in the world to learn about genetic variants unique to the Indian population. Countries including the United Kingdom, China, and the United States have launched similar programs. Sequence at least 1,00,000 genomes of their population.
What is genome sequencing?
The human genome is the complete set of deoxyribonucleic acid (DNA) that resides in the nucleus of every cell in every human body. It contains the complete genetic information responsible for the development and functioning of the organism. DNA consists of a double-stranded molecule formed by four bases – adenine (A), cytosine (C), guanine (G) and thymine (T). Each base on one strand pairs with a complementary base on the other strand (A with T and C with G). In total, the genome is made up of approximately 3.05 billion such base pairs. .
While the sequence or order of base pairs is the same in all humans compared to mice or other species, there are differences in each human’s genome that make them unique. The process of deciphering the sequence of base pairs to decode a human’s genetic fingerprint is called genome sequencing.
In 1990, a group of scientists began working on determining the complete sequence of the human genome under the Human Genome Project. The first results of the complete human genome sequence were given in 2003. However, a small percentage of repetitive parts remained to be sequenced. The Human Genome Project released the latest version of the complete human genome in 2023 with a 0.3% error margin.
The cost of sequencing varies depending on the methods employed or the accuracy expected. Since the initial rough draft of the human genome was made available, companies have aimed to reduce the cost of producing a fairly accurate “draft” of any individual genome – it has now fallen to one-tenth, or about $1,000 or less (about ₹70,000).
Genomic sequencing has now evolved to a stage where large sequencers can process thousands of samples simultaneously. There are several approaches to genome sequencing – including whole genome sequencing or next generation sequencing – which have different advantages.
What made the process of whole-genome sequencing possible? human genome projectIt is now possible to read an individual’s individual genome to identify differences from the average human genome. These differences or mutations can tell us about each human being’s susceptibility or future susceptibility to a disease, their response or sensitivity to a particular stimulus, etc.
What are the applications of genome sequencing?
Genome sequencing has been used to evaluate rare disorders, pre-conditions for disorders, even cancer from the perspective of genetics rather than diseases of certain organs. About 10,000 diseases – including cystic fibrosis and thalassemia – are thought to result from a single gene malfunctioning.
In the past decade, it has also been used as a tool for prenatal screening to check whether a fetus has genetic disorders or anomalies. Thennew York Times Notes that the Nobel Prize-winning technology CRISPR, which relies on sequencing, could potentially allow scientists to repair disease-causing mutations in the human genome. Acute biopsy, where a small amount of blood is examined for DNA markers, can help diagnose cancer long before symptoms appear.
However, in public health, sequencing has been used to read the code of the virus – its first practical use was in 2014, when a group of scientists at MIT and Harvard sequenced Ebola samples from infected African patients to show how genomic data of the virus could reveal hidden routes of transmission, which could then be blocked, thus slowing or even stopping the spread of the infection. Experts say that as sequencing becomes cheaper, every human’s genome could in the future be sequenced as part of routine health care to better understand individual molecular biology and health.
Genomics has many benefits at the population level as well. Advanced analytics and AI can be applied to essential datasets created by collecting genomic profiles across populations, leading to a greater understanding of the causative factors and potential treatments for diseases. This will be particularly relevant for rare genetic diseases, which require large datasets to find statistically significant correlations.
How did it help during the pandemic?
In January 2020, at the beginning of the pandemic, Chinese scientist Yong-Jen Zhang sequenced the genome of a new pathogen causing infections in the city of Wuhan. new York Times The report states. Mr Zhang then shared it with his virologist friend Edward Holmes in Australia, who published the genomic code online. Virologists, epidemiologists and pharmaceutical firms then started evaluating the sequence to understand how to combat the virus, track the mutated variants and their intensity and spread, and come up with a vaccine. This information was also used to create diagnostic PCR machines.
To enable an effective COVID-19 pandemic response, researchers tracked emerging variants and conducted further studies regarding their infectivity, immune escape, and ability to cause severe disease. Genomic sequencing became the first step in this important process. The aim of genome sequencing here was to understand the role of certain mutations in increasing the infectivity of the virus. Some mutations have also been linked to immune escape, or the ability of the virus to escape antibodies, and this has implications for vaccines and vaccine manufacturers.
During the pandemic, the United States and the United Kingdom stepped up genomic sequencing, tracking emerging variants and using that evidence to drive timely action.
India also set up a sequencing framework, and the Indian SARS-COV-2 Genomics Consortia (INSACOG), a consortium of laboratories across the country, was tasked with scanning coronavirus samples from patients and flagging the presence of variants known to increase transmission internationally. The bulk of its efforts focused on identifying international ‘variants of concern’ (VOCs) flagged as particularly infectious by the World Health Organization. Samples of international travelers who arrived in India and tested positive were sent to INSACOG to determine the genomic variant.
As of early December 2021, INSACOG had sequenced approximately 1,00,000 samples. It was also tasked to investigate whether certain combinations of mutations are becoming more widespread in India.
In the later stages of the pandemic, around December 2022, when more than 90% of the adult population was already fully vaccinated and more than one-quarter of adults had received a boost, sequencing helped target efforts to reduce infections. The health ministry urged states to increase sequencing (and not increase testing) to track new variants as the virus has evolved by accumulating mutations.
What is the importance of Genome India Project?
India’s 1.3 billion-strong population includes more than 4,600 population groups, many of which are endogamous. Thus, there is great diversity within the Indian population, with disease-causing mutations becoming more frequent within some of these groups. A note from the Indian Institute of Science (IISc) said population-based or disease-based human genetics research findings from other populations of the world cannot be extrapolated to Indians. But despite having a large population with diverse ethnic groups, India lacks a comprehensive inventory of genetic variations.
Creating a database of the Indian genome allows researchers to learn about genetic variants unique to India’s population groups and use them to optimize drugs and treatments. About 20 institutions across India are involved in the project, which has been analyzed and coordinated by the Center for Brain Research at IISc, Bangalore. The Centre’s Department of Biotechnology says the project will help uncover the genetic basis of “chronic diseases currently on the rise in India, (for example) diabetes, hypertension, cardiovascular disease, neurodegenerative disorders and cancer”.
