Missing piece?? How to fix

By Emma Betuel

on November 24, 2018

Filed Under Health & History

 

The Human Genome Project, which began in the 1990s, was Homo sapiens’ successful attempt to map out the entirety of our species’ DNA. It produced the human reference genome, a finely polished collection of human DNA that’s crucial for genetics research and genetics testing services around the world. Integral as it has been to the science community, two researchers at Johns Hopkins University have discovered that the reference genome is missing a piece or two — well, 296,485,284 base pairs of DNA, to be exact.

The reference genome is an essential map of human genetic material that is used as a basis for comparison. When we sequence our own DNA for insight into health, family history, and future disease risk, we chop up the sequence into lots of little pieces and compare stretches of it to the reference genome, looking for areas where we differ. The fundamental problem with this, the scientists write in a recent paper in Nature Genetics, is that the reference genome is based largely on a single person. Considering the myriad genetic differences among the 7.7 billion people alive today, that’s obviously not ideal.

“If once in a while there were mutations in that chromosome that did cause problems, you’d never be able to study those,” Salzberg says. “You’d never be able to observe them if you relied exclusively on this reference genome.”

Let’s be clear: this research doesn’t provide evidence for some undiscovered chromosome. But it does suggest that we’re probably missing a lot when we use a single reference genome from some person called RPCI-11 as a basis for all of our analyses on the DNA of our entire species.

How Can We Fix It?

Instead of striving for a single universal reference genome, the team argues, we should have a bunch of reference genomes — perhaps one for each population of interest.