Dr. Pankaj Kumar Singh
Genetics is the scientific evaluation of heredity and genes – of how certain traits or qualities are passed from one to the next generation by virtue of diversity in DNA sequences. The elemental unit of heredity is DNA molecule, which consists of biological and chemical instructions that are responsible for uniqueness of each species. Genetics demand those genes or part of genes which functions are specific, well explored and till date these identified genes numbers are still limited. In present scenario, scientists are investigating more number of genes to explore their role in various fundamental activities in human body, disease cause and response to drug. In biomedical research, this is the need of current hour towards establishing relation between genetics and various diseases including response to drug.
Genomics, in contrast investigates all genes of an organism’s – termed as a genome. Basically, genome represents a complete copy of the almost 3 billion DNA base pairs that synthesize the genome of human. In recent years, scientists have analysed huge amounts of sequence data to evaluate variations in relation to heath, disease and drug response by application of high throughput technologies such as whole genome sequencing, DNA microarrays, and bioinformatics tools. In humans, we can say that searching variations in human through about 3 billion DNA base pairs involving approximately 23000 genes. Genomics became most exciting emerging field of biology than genetics due to development of newer DNA sequencing methods and technical advancement in computational biology.
In May 2013, Angelina Jolie stated that she had a BRCA1 mutation derived from genetic testing and opted for a double mastectomy. This news gained extensive media coverage due to her celebrity status and brought issue of genetic testing into limelight. More recently, researchers made genetic evaluation of 8 hair samples to find out real cause of death of Ludwig van Beethoven, the most celebrated music composer’s death and identified genetic predisposition to liver disease, hepatitis B infection with alcohol consumption towards his death.
Genomics derived knowledge and understanding can be applied in various fields such as social sciences, medicine, and biochemistry including biotechnology. Till date, applications of has already made significant place in many areas, however existence of potential to revolutionize areas of genomics in relation to human life and other’s even further in the near future. Recently, new possibilities have been explored for researchers and clinicians via technological advancement to acquire genomic data, as informative data can be acquired more skilfully incomparision to previous years. This has driven to a significant clinical understanding of genomics and explores role of genes in causing or prevention of the disease and response to drug.
Decryption of the whole-genome sequencing is one of the most valuable, affordable accomplishments of modern science, which has increased global progress to evaluate and acquire reliable genomic data. Undoubtedly, it has led to significant improvement in clinical management of disease; the way inherited diseases are diagnosed, treated, and prevented. The Human genome project has been initiated in 1990 to sequenced 20,000 genes, their interactions and spotlight on targeted therapy as an effective disease management system. Almost two decades after the project, some remarkable findings contributing to the healthcare revolution has been identified. More recently, we have seen application of next generation sequencing in identification of new coronavirus variant. Presently, it is possible to sequence the human genome in matter of days, and at an affordable cost. Technological advancements in sequencing methods have paved the path towards early diagnosis and targeted treatment of different diseases including various malignancies and rare disorders.
DNA sequencing based approach in healthcare industry utilizes the individual’s genomic data to predict risk of developing certain diseases and prevention of disease in early stage. Precision medicine is an inventive idea, an emerging applied filed of genomics that focus on a patient’s genetic makeup to plan treatment they receive. Moreover, targeted therapies associated with specific genome in oncology have been already introduced in medical practice for treatment and prevention of disease. With recent progress and advancement in genome sequencing technologies, more precise and appropriate personalized treatment options are available in healthcare.
The Current Genomics scenario
Presently, characterization of specific genetic mutation is possible through genomics to deliver much effective treatments. Today, genomics is translating our understanding of various diseases such as cancer, diabetes mellitus, metabolic syndrome and heart diseases. Genomics has made significant contribution in field of oncology and helping clinicians to assign appropriate oncology treatment approach for patients by identifying mutations and shared alterations, deletions and insertions, therapeutic targets, chromosomal rearrangements and loss of heterozygosity. Moreover, high-throughput genomic technologies have the potential to enable early diagnosis, prediction of recurrences and treatment failure. Conclusively, utilizing the power of genomics in health care will immensely improve patient outcomes and make diseases more treatable.
An overview of DNA Sequencing
More recently, global pandemic has gained our attention back to sequencing technologies to identify new variants of SARS-CoV-2 virus and tools for management of outbreak. Identification of mutations by genome sequencing has enabled information about different features of SARS-CoV-2 virus including pathogenicity, infectivity, transmissibility and/or antigenicity. Genome sequencing has assisted in identification of new variants of the SARS-CoV-2, interpretive decision of healthcare and beneficial in development of rapid and point of care diagnostic tests. In this quest, integration of genome sequencing practices is need of hour for any threats in near future. Moreover, Phase 2 & 3 clinical trial studies involving drug testing can have inconsistent findings on different patients with unique genetics showing different response even as the same drug is being tested. As a result, many patients do not get benefit from anew developed drug because of patients are suffering from underlying issues that might be undiagnosed yet. With the combination of genomics, clinical trials would be more efficient and specific by involving different treatment pathways that would be much more beneficial in treatment of diseases.
Genomics Future
Pharmcogentics is aimed to provide more efficient treatment by identification of patients at a higher genetically-determined risk of adverse effects or an inadequate response to medication. Presently, it is evident that genes influence most of the metabolic activities of human body. Advancements in genomics field and sequencing technologies have shown that promising approach towards emerging fields like gene editing, gene therapy. Gene editing a tool which involves identification of altered genes, sniped out of the human body and replaced with healthy genes, performed in genomic labs. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is rapidly growing gene editing tool used in research and patients. Other gene editing tools like Zinc Finger Nucleases, TALENs, MegaTALS, CAS-CLOVER, and MegaNucleases are underway. Recently in the US and Europe, Victoria Gray and other trial participants has received CRISPR-based sickle cell disease treatment, which will be the first approved CRISPR-based therapy for treatment of sickle cell disease. This is a milestone in realizing the potential of CRISPR to improve human health. CRSPR therapeutics is already under phase 2 & 3 of clinical trials for various diseases such as blood disorders, Leukemias & Lymphomas, genetic blindness, diabetes, HIV/AIDS and cardiovascular diseases. Various other technologies have already under developmental phases of clinical trials, although ethical concerns and data privacy issues remain.
Genomics is in all ways systematize the individual rather than the disease as we move away from the one size fits all approach.
(The author is Assistant Professor in the Department of Biochemistry, AIIMS Vijaypur, Jammu)
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