The Genomic Revolution
Researching DNA sequencing could provide a route map for better living
All of us begin our life as a single cell, roughly the width of a human hair. Within this cell is the human genome, made of 3 billion bases of DNA that carries the instructions for life. In 2001, after a decade of work involving scientists from over 16 countries, the sequence of the first human genome was completed at a cost of $3.8 billion.
Over the past decade, advances in DNA sequencing technologies have made it possible to sequence a human genome for $1,000 in a week’s time. A number of groups, using DNA sequencing, have begun to catalogue variations in human populations. This has enabled us to understand human migration and population history. For instance, sequencing of extinct hominids such as Neanderthals and Denisovans has provided clues to our evolutionary past.
This sequencing revolution is beginning to change the way medicine is practiced and drugs are developed. Cancer is caused by deleterious mutations that accumulate in the genome. Inherited genetic disorders arise due to mutations in DNA that are passed on at birth. Increased risk for developing breast cancer, among others, is linked to variations in genes such as BRCA1 in the genome. Sequencing an individual’s genome or the tumor genome and comparing it to a reference human genome has helped identify the differences that contribute to the disease. In many cases, it has the potential to help with treatment decisions.
Traditional blood tests involve biochemical analysis, cell type and protein assessments. Blood also contains DNA, which, until now, was ignored. In pregnant mothers, the blood also contains DNA from the fetus. Scientist have developed methods that can sequence the cell-free DNA in mother’s blood to monitor the genetic health of a developing baby. The same technique can be used to assess an individual’s health and catch diseases like cancer well before they manifest. Sequencing also has been applied to understand the microbiome, an important component of our skin, gut and other body surfaces.
The genomics revolution has enabled sequencing a large number of organisms including bacteria, plants and animals. While it has confirmed the common evolutionary origin of life on earth, it has provided the code for a number of life forms. Sequencing of plants including cereals like rice and wheat has set the stage for rapid crop improvement. Understanding genomes of livestock such as cattle and goats has created a rich resource of genetic variations that can be used to produce animals with superior traits. The sequencing advances have enabled deciphering DNA from endangered plants and animals. Such efforts have enabled conservation through effective breeding strategies.
In 2012, CRISPR/CAS9, application of a precise genome editing/engineering technology was demonstrated. This technology combined with the genome sequence information is poised to have a profound impact on our ability to dissect, analyse and understand biological systems. It has the potential to manage and/or cure human disease. The editing combined with sequencing will enable rapid crop and livestock improvements that have the potential to end hunger and improve the standard of living across the world.
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