What is Genome?
- A genome is an organism’s complete set of DNA. It is a collection of all the genes and the regions between the genes contained in our 23 pairs of chromosomes.
- Each chromosome is a contiguous stretch of DNA string, i.e., the human genome consists of 23 different strings, each composed of millions of individual building blocks called nucleotides or bases [adenine (A), cytosine (C), guanine (G), and thymine (T)].
- These bases or building blocks (A, T, G and C) are arranged and repeated millions of times in different combinations to make all of our 23 chromosomes.
- The genome contains all the data that is needed to describe the organism completely — acting essentially as a blueprint. The genome can be understood through the process described as genome sequencing.
What is Genome Sequencing?
- Whole-genome sequencing is the decoding of the entire DNA present in the human cell, i.e, determine the precise order of the four bases and how they are arranged in chromosomes.
- This data can be analysed to understand the function of various genes, identify genetic mutations and explore how genetic mutations impact gene functions and cause certain congenital diseases.
Applications of Genome Sequencing:
- Disease Diagnosis and Treatment: Genome sequencing can identify genetic mutations and variations that contribute to the development of diseases. It has been used to evaluate rare disorders, preconditions for disorders and even cancer from the viewpoint of genetics.
- Nearly 10,000 diseases — including cystic fibrosis and thalassemia — are known to be the result of a single gene malfunctioning.
- Genome sequencing can be used to read the codes of viruses, which can be used to understand how to combat the virus, track mutating variants, and develop a vaccine.
- In 2014, a group of scientists from M.I.T and Harvard sequenced samples of Ebola from infected African patients to show how genomic data of viruses could reveal hidden pathways of transmission.
- In January 2020, at the start of the CoVID-19 pandemic, scientists sequenced the genome of a novel pathogen causing infections in Wuhan, China.
- Personalised Drug Development: Can identify genetic targets for drug development and testing, leading to the development of more effective and personalised drugs.
- Prenatal Screening: Can be used as a tool for prenatal screening to investigate whether the foetus has genetic disorders/anomalies.
- Agriculture: Can help identify genes that contribute to desirable traits in plants and animals, allowing for the selective breeding of crops and livestock.
- Forensics: Genome sequencing can be used to identify suspects in criminal investigations and to establish paternity in cases of disputed parentage.
- Evolutionary Biology: Can help trace the evolutionary history of species and understand the mechanisms underlying evolution.
Genome Sequencing Projects:
Human Genome Project
- In 1990, a group of scientists began working on the Human Genome Project which was an international programme that led to the decoding of the entire human genome.
- Completed in April 2003, the HGP, for the first time, gave the ability to read nature’s complete genetic blueprint for building a human being.
IndiGen:
- IndiGen is a program initiated by the Council of Scientific and Industrial Research (CSIR) from April 2019 to October 2019.
- Aim: To sequence the whole genomes of 1029 individuals from diverse ethnic groups across India.
- The project has already been completed and the results have been published in the scientific journal Nucleic Acid Research. The data can be used to study the genetics of the Indian population and to develop new treatments for diseases that are common in India.
Genome India Project:
- Genome India Project (GIP) is a government initiative to execute whole genome sequencing and subsequent data analysis of 10,000 individuals representing the country’s diverse population by the end of 2023.
- Launched by: Department of Biotechnology in January 2020.
- Aim: To create a comprehensive reference database of genetic variations in the Indian population and identify genetic variations that are associated with common and rare diseases prevalent in the Indian population.
- The project is being carried out in collaboration with several institutions, including the National Centre for Biological Sciences, the Institute of Genomics and Integrative Biology, and the Centre for Cellular and Molecular Biology.
Need of GIP:
- India has around 1.4 billion population consisting of over 4,600 population groups, many of which are endogamous (disease-causing mutations often amplified within some of these groups). But despite being a large population with diverse ethnic groups and huge prevalence of rare diseases in the country, India lacks a comprehensive catalogue of genetic variations.
Significance of GIP:
By unravelling genetic variants unique to India’s population groups, the project has the potential to:
- Improve disease diagnosis and prevention: Identifying genetic markers associated with diseases can lead to earlier diagnosis, more effective treatment, and preventive measures. E.g., Identify prevalence of congenital disorders like sickle cell anaemia and thalassemia in certain tribal groups.
- Advance precision medicine: GIP's genomic data will be instrumental in implementing precision medicine approaches, targeted therapies, and tailoring healthcare to an individual's genetic profile.
- Empower genomic research and innovation: By sequencing the genomes of a large and diverse group of individuals, the GIP will establish a baseline reference genome for the Indian population. This reference genome will be invaluable for researchers studying genomics in India and contributing to the global understanding of human genetics.
Important genome sequencing initiatives across the globe:
| S.No. | Initiatives | Initiated by | Details |
| 1. | Human Genome Project | Lead by USA | Launched in October 1990 and completed in April 2003. |
| 2. | deCODE | Ireland | Large-scale population genetic studies initiated in Iceland in 1996. |
| 3. | Diversity Human Genome Initiative | Various pharmaceutical companies | Sequence five lakh individuals of African ancestry (Launched in 2023) |
| 4. | 100K Genome Project | UK | Launched by the UK government in 2012 to sequence 100,000 genomes. |
| 5. | 1+ Million genomes | European Union | Sequence genomes of at least one million people from across Europe by 2027. |
| 6. | Genome Asia 100K initiative | Asia | Sequencing genomes of 100,000 individuals from diverse ethnic groups across Asia. |
| 7. | IndiGen | India | Sequence whole genomes of 1029 individuals from diverse ethnic groups across India. (Completed in 2019) |
| 8. | Genome India Project | India | Execute whole genome sequencing and subsequent data analysis of 10,000 individuals in India till end of 2023. |