If genomes are going to revolutionize personalized medicine, the first step will be sequencing the genome accurately.
It bears repeating just how far this tech has come: the price of sequencing a genome is rapidly coming down, as is the time it takes to do a sequence. It’s getting so easy that the price point is already well within the means of many middle class Americans, and the technology might soon prove useful enough to save lives. Proponents say that, in the future, personalized medicine will allow doctors to determine the specific genetic variants that predispose their patients to certain diseases, which will then help doctors to devise individualized—and more effective—treatments.
But with roughly six billion base pairs in the human genome, creating a truly accurate gene sequence is no easy task. Even the best sequencing techniques can have an error rate around 1 percent, which adds up to hundreds of thousands of errors. When diseases depend on single nucleotide insertions or changes, those errors can mean the difference between a misdiagnosis and an accurate one.
A group of researchers with the US government’s National Institute of Standards and Technology is trying to solve that problem with a program called Genome in a Bottle. With academic and commercial partners, the group is trying to create what is essentially one “perfect” human genome that can be a reference for sequencing labs. Though every genome is different, the places where sequencing errors most commonly happen are fairly well understood, and by comparing one sequence with a reference genome, doctors and researchers would be able to tell if they’ve made a mistake.
“We’re sitting here with billions of data pairs—it boggles the mind try to get that much information accurately determined,” said Marc Salit of NIST’s Genome Scale Measurements Group. “Even when we think we’re getting it right, a few missing bases or additional ones can make a huge difference.”
Salit and his colleague, Justin Zook, recently published a study in Nature Biotechnologydiscussing their solution to the problem. According to Salit, by sequencing the same genome many times and comparing the base pairs, they can create a reference that is much more accurate than what we already have.