Scientists Update Human Genome Making it More Inclusive
Scientists have released a new draft of the human genome which they say will help advance medical understanding and deliver treatments that benefit patients of all races, ethnicities, and ancestries. A genome is like a blueprint or DNA instructions for how living creatures function. On average, humans have about 0.4% genomic variation from person to person. That might not sound like much, but these minor differences contribute to each person's uniqueness. They also affect health, chances of developing diseases, and whether a person will respond to medical treatment. The human genome is also enormous, consisting of 3.2 billion base pairs or sets of genetic "letters," allowing for genetic differences between individuals and populations worldwide.
The first human genome version was released in 2001 and completed only last year. Scientists based 70% of the original version's DNA sequence on one white male volunteer. So the standard doctors have been using to compare all patients to has been heavily weighted toward people of White, European ancestry. Dr. Adam Phillipy, a co-author of the new pangenome, says this created a reference bias. "Using a single reference genome sequence for every person can lead to inequities in genomic analyses. For example, predicting a genetic disease might not work as well for someone whose genome is more different from the reference genome."
As limited as the previous human genome was, it helped unlock thousands of medical enigmas and led to a revolution of more targeted and effective personalized treatments. The new pangenome includes the DNA of 47 people, including individuals of African, Asian, Caribbean, American, and European ancestry. Their DNA sequences add 119 million base pairs to the 3.2 billion previously known ones. Scientists hope to expand the genome over the next two years to incorporate 350 more genetic blueprints worldwide. Even with these planned upgrades, no single genome can represent the genetic diversity of our species.
Dr. Eric Green, director of the National Human Genome Research Institute, looks forward to the new understanding and treatments that will come from this more inclusive genome version. "We will look back on how we practiced medicine, and we will be astonished at how barbaric it was." This and the next planned upgrade are important steps in moving us toward a future in which genomic medicine benefits everyone. The pangenome appears in this week's edition of the journal Nature.