Johns Hopkins University
Publication Date: January 1, 2015
“Discover your ancestral origins and lineage with a personalized analysis of your DNA,” advertised 23andMe, supposedly the largest DNA ancestry service in the world (1). For $99, you can send them a sample of your saliva and they’ll tell you whether your great-great-great grandfather was Sub-Saharan African. They’ll give you health reports, too, such as your 49% likelihood of developing heart diseases. Ladies and gentlemen, relinquish all your fears: 23andMe is the next medical panacea of the 21st century. Forget about the doctor, just spit into a vial and the good scientists at the company will diagnose all of your health problems.
Welcome to the age of genomics. The age during which all that matters is genetics. The age of sensationalized medicine.
When Watson and Crick discovered the structure of DNA, a pandora box was opened: mankind learned how genetic blueprint was stored (2). Every gene, constructed from sequences of fundamental building blocks, expresses a different protein, giving rise to observable traits such as eye color. Following this Nobel Prize was a revolution in biotechnology. We began figuring out how to manipulate genetic information, even engineering all kinds of animals to express or lack different types of genes. The first high point of the genomics era is the $3 billion Human Genome Project, which aimed to sequence and map our genome (the entirety of genetic blueprint) (3).
While the Project gave us further insight about the biology underlying ourselves, it also inspired another biotechnology microevolution that’s beginning to grow out of proportions: personalized medicine. Countless companies began popping up to offer a new type of service to the public. For the first time ever, people with obscene amounts of money could have their entire genome sequenced, block to block. Even hospitals in Massachusetts have jumped on this technological bandwagon, offering personal genome sequencing services for $9000. “Offers Doctors and Patients Improved Diagnosis, Treatment” read the press release (4). During his Ted Talk, James Watson talked about the lofty goal of sequencing the genes of cancer patients, believing this genetic screening to be “very, very useful” (5). How so? Genome sequencing could pinpoint to single mutations (or faults in DNA) that explain complex disease cases. In more fancy terms, sequencing our entire DNA may allow doctors to develop individually tailored care that fits with each person’s unique genetic predisposition. Medicine has gotten personalized down to the level of a single molecule!
I’m sorry for being a party pooper, but genome sequencing bears zero medical significance (or at least as life-saving as the media has made it). 98% of our genetic information doesn’t express anything (6). Moreover, the results of genome sequencing all depend on the “control”: your DNA sequences will usually be compared against those of another person. Any differences that show up will be read as possible mutations. Yet, every person’s genome has all kinds of genetic variants. There exists no “standard” human genome that can serve as a reliable control. A new report published in Science show that even individual cells within a single human brain possess significant genetic variations (7). As Dr. Macosko from Harvard Medical School put it, “genome sequencing has instead generated its own needle-in-a-haystack problem: distinguishing the variants that truly matter to an illness from the far-larger number of functional variants that are present in every genome” (8). In other words, among the countless number of genetic variants and “junk” material, how can we find the significant mutation that truly underlies an observable trait?
It has been said that thanks to genetic sequencing, identifying critical mutations has been crucial to solving many medical cases in the last decade. Great, you’ve identified some sort of mutation, but so what? We have identified numerous genes that underpin genetic disorders a long time ago, yet these same disorders still remain incurable. Take Thalassemia for example. It’s an autosomal recessive disorder thought to be amenable to gene therapy. Yet, decades after discovery of the Thalassemia-causing gene, still no progress in treatment. Don’t think that knowing every single sequence of your DNA will lead to a cure. Steve Jobs spent $100,000 to sequence his genome, yet no doctor was able to cure his cancer.
A discussion on genetics would not be complete without paying visit to the nature versus nurture concept. In the midst of this sequencing fad, it’s easy to forget that our genes don’t determine everything: environmental factors matter, too. Rather than “determinists”, genes should be viewed as “potentialists” that are modulated by external influences such as activity and diet. Of course, the body cannot function beyond the limits set by biology, but total reliance on genetics to predict our lives is absurd.
While exciting, personalized medicine is still an iffy concept that requires more work. Thank goodness the FDA recently stopped 23andMe from giving health advice to its customers. However, it still didn’t stop people’s frenzied obsessions with sequencing their genetic blueprint as they waste away thousands of dollars. Sensationalized medicine sells, and that’s all that matters to for-profit private organizations. Here’s something that works better than personalized medicine that’s also cheaper: preventive medicine. Exercise regularly. Eat a healthy diet. Get enough sleep. Preventing the fire before it starts is much easier than trying to put it out. Could personalized medicine be a legitimate therapeutic strategy in the future? Absolutely, but our current level of knowledge is not sufficient for meaningful interpretations of long strands of genomic sequences. Don’t buy into the media and follow conventional health wisdom, and you’ll save a lot more money as well as yourself.
1) 23andMe – Genetic Testing for Ancestry. (2013). Retrieved from 23andMe website: https://www.23andme.com
2) Watson, J., & Crick, F. (1953). A Structure for Deoxyribose Nucleic Acid. Nature.
3) NIH Fact Sheets – Human Genome Project. (n.d.). Retrieved from NIH Research Portofolio Online Reporting Tools website: http://report.nih.gov
4) Partners Launches Service to Offer Patients Clinical Whole Genome Sequencing and Interpretation [Press release]. (2013, August 26).
5) How I Discovered DNA. (2005). Podcast retrieved from http://ed.ted.com
6) Elgar, G., & Vavouri, T. (2008). Tuning in to the signals: noncoding sequence conservation in vertebrate genomes. Trends in Genetics.
7) McConnell, M., Lindberg, M., Lennand, K., Piper, J., Voet, T., & Cowing-Zitron, C. (2013). Mosaic Copy Number Variation in Human Neurons. Science.
8) Macosko, E., & McCarroll, S. (2013). Our Fallen Genomes. Science.
Image taken from Pacific Standard.