Although there has been a recent boom in DNA research, little is known about the connection between DNA and disease in African Americans. This is because most genetic research studies intentionally limit enrollment to a single population – usually, northern Europeans – since the analysis is easier to carry out in groups tracing ancestry to just one continental region.
Since discoveries made in one population aren’t always applicable to other ancestral groups (a genetic variant might not be associated in other populations, or might have a different effect) it is important to carry out additional research. Studying African Americans is complicated, though – most members of this group trace their ancestry to both Africa and Europe and it isn’t straightforward to figure out which pieces of their chromosomes came from each continent, something that is important for teasing out links between DNA and disease.
In this example of an ancestry painting from 23andMe, an African-American woman has DNA that traces to Europe (blue), Africa (green) and Asia (orange). Theoretically, a genetic factor identified in Europeans could be applicable if she inherited the version of the genetic factor tracing to Europe as opposed to the version tracing to Africa or Asia. It isn’t always this straightforward, however, and association studies should be carried out in African American cohorts in order to confirm or negate that the genetic factor is applicable.
Bridging the gap in research is particularly important for diseases that affect African Americans more than the rest of the population. Prostate cancer is a prime example. African American men have the highest rate of prostate cancer in the United States and are more than twice as likely as men of other ethnicities to die of the disease (62% in African American males versus 26% in American males of European descent). These numbers are staggering and point to disparities not only in medical access and treatment but also in scientific research.
At 23andMe we strive to provide meaningful genetic health reports to individuals of all ethnicities but are often hampered by the lack of published studies in non-Europeans. The need for more research involving African Americans is further supported by recent studies showing that many factors linked to prostate cancer in European populations aren’t applicable to African Americans and by the fact that less than one-third of our current health reports provide results applicable to people with African ancestry.
23andMe recognizes that research has lagged in this area and in an effort to reverse this trend has launched Roots into the Future, an initiative aimed at discovering connections between DNA and disease in 10,000 African Americans. Our aim is to provide disease risk reports for everyone – regardless of their ancestral origins – and you can be a part of this exciting process.
February is Black History Month – see our previous posts on sickle cell disease and African ancestry!