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Publications total: 16
  Feb 23rd,2016

Personalized DNA sequencing as a part of routine healthcare check-up: Opportunities and challenges

Introduction:

Since the discovery of the DNA, mankind has come a long way in terms of understanding the functionality of a living organism. The secret lies in the nucleus of every cell that accommodates the DNA, which in turn harbours thousands of genes. Hence, understanding the functionality of every gene is the way to unravel the mysteries of life. One of the greatest achievement of the 21th century has been the advent of a new technology called DNA sequencing that makes it possible for the scientific community to ascertain and monitor the functionality and interactions of a whole set of genes on a genome in a single array. DNA sequencing has been highly conclusive in terms of underlying multiple gene interactions that defines the functionality of an organism, compared to the earlier techniques, where studies were restricted to one gene at a time, ending up providing only a vague picture. The successful completion of the human genome project in 2003 created a whole new range of possibilities and benefits in the field of medical research, making it possible to understand human and animal diseases at the molecular genomic level. It was now possible to genotype pathogens such as bacteria and virus that allowed the researchers to conceptualize and formulate treatment strategies that are specifically attenuated to the host. In essence, a whole new range of possibilities were opening up after the unravelling of the human genetic blueprint.

Genomic research has come a long way since that time both in terms of the cost that goes into sequencing an entire genome and the information that is available to mankind. The cost of sequencing the human genome for the first time was around $2 billion and the entire process, when seen in light of the techniques available today, was slow and cumbersome (Carson, 2016). Today, researchers are looking forward to sequencing devices that would easily fit into a pocket and would sequence the entire human genome within hours at around $100. We are new entering the era of the so called "Personal genomics" where genomes of individuals will be sequenced within a very short time to gather critical genetic information so that treatment can be highly customize according to the host genetic makeup. The human genome draft presented by the human genome project in true sense is a reference genome created by sequencing DNA taken from a number of individuals. But as it is known, every individual genome is very unique and thanks to the advancement in sequencing technologies it is now practical to get an individual genome sequenced at an affordable cost (Yourgenome.org, 2015).


The promise of personal genome sequencing:

Fast DNA sequencing as a part of routine medical check-up may soon became a reality with the sequencing cost going below the $1000 mark. According to Pennisi (2012), the pace at which DNA sequencing technology is advancing will easily outrun the Moore's law that states that computing power doubles and the cost of computing comes down by half every 18 months (Harth, 2012). A group of researchers from Arizona State University led by Dr. Stuart Lindsay who is the director of the Biodesign Institute's Center for Single Molecule Biophysics are working towards a DNA sequencing technology that will make sequencing a part of routine medical check-up. Anticipated to be within a cost range of $1000, the technology will decipher the genetic knowledge hidden in an individual's 3-billion long DNA sequence and allow development of highly customized and tailored approaches for disease diagnosis and treatment (Esciencenews.com, 2010). Sequencing the genome of an individual will help researchers and geneticists understand every aspect of an individual's physiology in terms of his or susceptibility to certain diseases or the way in which the individual would respond to a certain drug. Doctors can use this information to prescribe medicine that is most appropriate for the patient based on his or her physiological status. This is essentially pharmacogenomic knowledge that can be used to maximize the efficacy of drugs and minimize any deleterious side-effects to the maximum possible extent (Yourgenome.org, 2015). During a routine check-up, an individual's genetic information can also be used by researchers to determine if he or she is suffering from or susceptible to acquiring a specific genetic disease. Geneticists can use the sequence data to detect the presence of genetic variants in the genome that may predispose an individual to a genetic anomaly or disease in future. A good practical example would be BRCA1 which is identified as breast cancer gene. Sequencing data will enable the researchers to determine if the patient carries the gene and if yes when and what are the chances that she will suffer from breast cancer during her life. Information such as this during a routine clinical exam could give the patient the critical early warning so that she can take the necessary preventive measures in a time-sensitive manner (Yourgenome.org, 2015).

Another major incentive of personal genome sequencing is for those couples who want to have children in the near future. Sequencing can help researchers know if one parent or both the parents are carrying any abnormal traits. Genetic anomalies such as cystic fibrosis may not manifest in an individual if he or she is a carrier of the recessive gene responsible for the condition. People who suffer from cystic fibrosis carried a defective gene called CFTR in chromosome 7 (Learn.genetics.utah.edu, 2016). The condition being recessive in nature, a child will only get cystic fibrosis if the defective gene is received from both the parents. In the event that only one parent passes the gene, the child will not manifest the symptoms and will remain a carrier of the condition. Personal genome sequencing of the parents will help determine if any of the parents are carrying the gene. If both the parents are carrying the recessive gene then there is a very strong probability that the new born child will have the condition. Under such conditions, an early and timely detection of the recessive gene in the genome of the parents will give them the time and the opportunity to look for other methods to bear a child such as in-vitro fertilization (Yourgenome.org, 2015). Personalized DNA sequencing will also allow researchers to study the individual microbiome present on the surface of the skin and mucosal tracts. The microbiome is essentially a microbial ecosystem that is highly specific to every individual. The microbiome takes shape through the interaction of several factors such as exposure to microbial organisms in early life, the innate immunity of the individual, exposure to drugs, the environment and even the diet. Recent advances in microbiome research have indicated that knowledge gained from such studies will help researchers get deep insights into conditions such as cancer, autism, obesity, cystic fibrosis and IBD that will eventually assist in formulating highly individualized treatment strategies (Larry Jameson and Longo, 2015).

A nanopore sequencing product manufacturing company called Oxford Nanopore Technologies based in the UK is playing a pioneering role in developing personalized DNA sequencing devices that would eventually become as ubiquitous as mobile phones. In a recently conference the company presented the first of its DNA sequencing devices that are actually the size of a cell phone. They envision a future where such small and affordable DNA sequencing devices are routinely used by doctors in their practices and the company has already published a virus genome draft sequenced by such a device. The researchers at the Oxford Nanopore Technologies believe that the device is already capable of handling much larger genomes such as the human genome and they are currently working towards releasing a device to the market that will cost less than $1000. Another researcher called Amit Meller from Boston University is working on an even more ambitious project to create a technology that will sequence an entire genome in just a couple of hours at a cost of less than $100 (Winslow, 2012).


Conclusion:

Personal genome sequencing as a routine activity in clinical check-up though a real possibility is still not available in the market. Given the current research trends in this direction there is no doubt in the fact that the market is all set to grow in the very near future and small sequencing devices will become a reality in hospitals and even small practices. From a medical perspective this will be a revolutionary development because as people know more about their genes they will be in a much better position to reduce disease risk or delay their onset. With the objective of speeding up the research endeavours in the personal genome sequencing sector, the personal genome project was launched in 2005 that aims to sequence one hundred thousand genomes collected from individuals across the globe. At this stage there is no risk in assuming that personal genome sequencing will become a reality in clinical practices in the very near future and will greatly improve the quality of people's lives.


References

Carson, M. (2016). Healthcare Networks of America - Star Trek Is Here. DNA Sequencing For Routine Checkups . [online] Hna-net.com.
Available at: https://www.hna-net.com/healthcare-network-insider...

Esciencenews.com, (2010). ASU scientists develop universal DNA reader to advance faster, cheaper sequencing efforts | (e) Science News . [online]
Available at: http://esciencenews.com/articles/2010/02/11/asu.sc...

Harth, R. (2012). Rapid DNA sequencing may soon be routine part of each patient's medical record . [online] ScienceDaily.
Available at: https://www.sciencedaily.com/releases/2012/05/1205...

Larry Jameson, J. and Longo, D. (2015). Precision Medicine—Personalized, Problematic, and Promising. Obstetrical & Gynecological Survey , 70(10), pp.612-614.

Learn.genetics.utah.edu, (2016). Cystic Fibrosis . [online] Available at: http://learn.genetics.utah.edu/content/disorders/s...

Pennisi, E. (2012). Search for Pore-fection. Science, 336(6081), pp.534-537.

Winslow, R. (2012). The Future of Medicine Is Now . [online] WSJ.
Available at: http://www.wsj.com/articles/SB10001424127887323530...

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