Genes or Genomes?
…And what’s the difference anyway?
The human genome captured headlines in 2003 when researchers first announced complete sequencing of all 3.2 billion base pairs. The endeavor took 8 years and many estimate over $1 billion. Hopes were high for implementing genetics into standard healthcare practice, but, a person’s genetics have been influencing healthcare and medical research for centuries. Until recently, physicians have gathered this information by proxy – through inquiries about the health of relatives, or at least the ones you could share genetic material with. We share the most DNA with our closest relatives: parents, siblings, and children. This relationship explains why certain diseases tend to run in families; genetics influence the chance of being diagnosed with certain diseases. However, even before the human genome was completely sequenced, we could read and compare smaller sections. Focusing on individual genes in this way has revealed much about the genetics underlying human health, and genes are now commonly sequenced to diagnose disease or guide treatment options.
You may be wondering, “If we can learn so much from individual genes, what’s the big deal about sequencing a person’s entire genome?” First of all, it was major accomplishment for modern technology. The computational power required to align all 3.2 billion base pairs in the correct order represents breakthroughs across computer science and biological statistics. Secondly, and of most importance to healthcare, researchers have found that only a small percentage of the genome has these protein-coding genes, roughly 2%. You may have heard the term “exome”, which refers to this protein-coding region. It quickly became apparent that many questions about genetics would require understanding how this seemingly extra 98% of DNA affects our physiology. Without a clear product to link with these regions of DNA, it has been more difficult to understand how the genome functions as a whole and which patterns most affect our physiology. More research that considers the whole genome is needed to resolve important questions about health and genetics.
Cost has been one of the largest barriers to widespread implementation. Still, genomic sequencing is becoming more common in research and medical laboratories. The speed and quality of genomic sequencing now makes it possible to test critically ill infants for thousands of conditions within days. Early diagnosis offers these infants early interventions that can greatly improve treatment outcomes. Industry has prioritized improving genomic and big data technologies with the hopes of delivering such a chance to more people. Reflecting on the ten year anniversary of announcing the first human genome sequence, Dr. Eric Green, the director of the National Human Genome Research Institute at the NIH, boasted about the field achieving a $5,000 genome in an interview with The New York Times. Today, companies are battling to be the first to offer the first genome for $100, and top CEOs predict the $100 genome will arrive within the next decade.
Push for an economical genome is industry’s contribution to improving medical genetics. The combination of genetic and environmental variables contributing to human diversity and health are so complex that will require widespread implementation of genomic sequencing before we can claim to fully understand the genome. Clearly it is more than a simple assembly of genes. Complex structural and regulatory messages are weaved into the genome, and many appear to play a role in disease. In the meantime, better sequencing can deliver fast and accurate to patients in need.