{"id":6422,"date":"2011-02-14T01:09:46","date_gmt":"2011-02-14T06:09:46","guid":{"rendered":"http:\/\/sepiamutiny.com?p=6422"},"modified":"2011-02-14T02:43:07","modified_gmt":"2011-02-14T07:43:07","slug":"the_undersample","status":"publish","type":"post","link":"http:\/\/sepiamutiny.com\/blog\/2011\/02\/14\/the_undersample\/","title":{"rendered":"The undersampled 1 billion (genetically that is)"},"content":{"rendered":"

\"nastruc1.png\"Two issues compel this post. One is practical. The other is more, shall I say, spiritual<\/i> (or at least fun!). In regards to the first, a few weeks ago<\/a> I reviewed a paper<\/a> which reported that the efficacy of response to a particular leukemia treatment regime was dependent on the amount of Native American ancestry an individual had. One has to be specific here, because many people who are white or black American have significant Native American ancestry (Brett Favre’s<\/a> paternal grandfather was Choctaw<\/a>), and many people who identify as Native American may not have as much Native American ancestry as others<\/a>. But for the purposes of this blog post, I want to bring to your attention the figure above, which I extracted from the paper. Its implications may pose a major problem in the future for South Asian biomedical research in the United States.\nThe chart is a bar plot where each thin slice is one of several thousand children suffering from leukemia, and you see in the color coding the amount of ancestry they have from a particular geographic region. So, most self-identified white children have predominantly European ancestry (red), though there are other elements (gray is African, purple is Native American, and green is Asian). Black Americans are mostly African, with a minority white component. Hispanic Americans are a mixture of various groups, depending on ethnicity. Finally, notice the Asian Americans: they are mostly Asian, but there is a minor European component!<\/b> What’s going on here? It turns out that the hospitals recording race information are actually using the government categories. So Asian American includes South and East Asians, two very different groups genetically. In fact, genetically South Asians are somewhat closer to Europeans, on average, than they are to East Asians. This is a problem, because as many of you know different ethnic groups have different responses to various drugs, not to mention divergent health risks (raise your hands if you have a parent with type 2 diabetes), and aggregating these very different groups in a genetic sense into one racial category is problematic for biomedical research. I also realized that I was part of the problem, insofar as I do recall blithely entering “Asian” into the forms that were occasionally presented to me. Of course I’m aware that I’m a different kind of Asian than a Korean person, but I hadn’t given though to the downstream effect of my decision to check the Asian box. And I’m someone with a life sciences background!<\/p>\n\n

Unfortunately, to add to this confusion of socio-political terms there is the problem that South Asians are one of the most undersampled groups when it comes to genetic variation in the world. Here are the South Asian groups in the Human Genome Diversity Project<\/a>:<\/p>\n\n