Less than a decade after the human genome was decoded and made available to the public, a new novelty has arisen: personal genetic screening. California-based Google biotech startup 23andMe and Icelandic deCODE Genetics have developed a service to provide personal information about your genome. This includes testing for links to genetically inheritable traits, including diseases like breast cancer and Alzheimer’s, as well as other traits ranging from personal I.Q. to vegetable taste preferences and music learning potential. The cost for this service is just under $1,000, or within reach of the average consumer.
Making this information so easily available to the general public is dangerous and has the potential to be very individually damaging. Genetic screens do already exist and are in wide use, except these are usually administered in a clinical setting with a physician or genetic counselor present to put the results in context.
The new technology does not actually scan the responsible genes themselves. It scans known SNPs (pronounced ‘snips’), or single-nucleotide polymorphisms. These can be thought of as trademark patterns in DNA that are known to be closely associated with a certain genotype, or genetic makeup. Although testing with SNPs can often give great insights into whether you have a good or bad version of a particular gene, it is by no means comprehensive. A genetic disease can result from problems with one of many genes, or from different versions of the same gene that might or might not be associated with the right SNP. It is not the end-all proclamation that a disease or health risk is imminent, or that personal health or personal potential is written in stone.
Knowing one’s genetic makeup might cause an unnecessary state of alarm, or lure someone into a false sense of security. The vast majority of diseases that have a genetic component can often be overshadowed by environmental or lifestyle factors. The absence of genetic red flags for heart problems is not a license to eat too many cheeseburgers. Having no genes for breast or prostate cancer does not make physicals and check-ups obsolete. These tests do not screen for all genetically determined factors of a particular trait, either because there is not a known SNP for a particular gene, or there are important genes that are still unknown.
It is also not too hard to imagine a scenario where one’s testing reveals a genetic susceptibility to a chronic disease, such as cancer. The results might generate an unnecessary state of fear. People often fear the worst, especially with an ambiguous result. It is very difficult for the average citizen, with no training in medicine or molecular genetics, to be able to put the results in perspective, as many people would be prone to jump to conclusions. These tests are not a black-and-white physician’s diagnosis, but a gradient of gray encompassing an incomplete scope of risks and factors.
For people that have not yet reached their potential or set their path in life (like myself and most people reading this) there is the possibility of being impaired by the results. Imagine a compassionate kid with great leadership and people skills who never pursues his or her dream of medicine because she does not have the SNPs for high intelligence. Too much faith in genetic predetermination could be very damaging.
This summer I had the opportunity to meet and talk to Dr. James Watson, Nobel Laureate and co-discoverer of the structure of DNA. He is also the first man to ever have his complete personal diploid genome sequenced, which was released to the public earlier this year. Unlike SNPs, having one’s entire genome decoded makes the risks for genetic diseases and conditions much less ambiguous. In a casual conversation he was asked if, having known what he knows now about his genome, he might have changed his lifestyle. He had recently found out that he was supposed to have developed macular degeneration by the age of 50. Approaching 80 years of age, his eyes still work. It is amazing what we know about our own genes and genetic diseases, but this knowledge is not all-encompassing, and the results are still best interpreted by a genetic counselor or physician.
The last 50 years have yielded monumental strides in man’s understanding of his own DNA. Genetic diseases can now be screened for and many adverse effects can be avoided. It is hard to convey the magnitude of what is known about our genes and what they do. Personal interpretation and application of this knowledge has a number of challenges and dangers on its own, especially without proper context. There exists the dilemma of knowing too much about our genetic potential, or taking the results too seriously. Tools yielded by technological progress can easily outstrip proper application, and in this new age of personal genetic screening, caution is needed.
Ryon Graf is a fourth-year genetics major. He can be reached at firstname.lastname@example.org.