A commentary published today in the journal Cell offers evidence of a stunning imbalance in the population groups that participate in genetic and genomic research, which can underlie some health care inequities. A glance at the pie chart below, which represents many genome-wide association studies (GWAS), reveals a telling tipping in favor of participants of European ancestry – 78 percent. Asians account for just 10 percent, and Africans 2 percent.
A GWAS is a sweeping look at single sites (SNPs) among a genome's 3.2 billion bases that differ among people. It's used to trace traits and conditions caused by multiple genes plus environmental influences. Algorithms deduce the associations from SNP data from people who share ancestry as well as a trait or disease of interest. "Ancestry" means shared heritage, manifest as hunks of genomes, and not what a sociologist might call race based on appearance.
The Eurocentric nature of the pretty pie charts and polygons of consumer ancestry tests of course reflect the market. The skewed representation in company databases can lead to surprise, confusion, and disappointment, when a population simply isn't yet on the radar.
In clinical studies, the stakes are higher. The overrepresentation of European whites can lead to sub-optimal diagnoses and therapeutic choices for people in other population groups. That's what prompted the commentary in Cell, "The Missing Diversity in Human Genetic Studies," from Giorgio Sirugo and Sarah Tishkoff from the University of Pennsylvania and Scott Williams of Case Western Reserve University. Citing examples from the long-studied single-gene conditions and others, they compellingly convey the importance of considering genetic ancestry in health care.
To continue reading, go to my DNA Science blog at Public Library of Science, where this post first appeared.