A sciencebase visitor emailed today, asking whether blood types really do correlate to different areas of the world and disease resistance in those particular areas. She suggested that maybe we should be living in those areas to give us protection. At least that’s what I think she was implying…
Well, there is no short answer, but I’m sure most people would rather not have where they live dictated by the disease protection status of their blood type. If I lived in a wealthy northern european city, but happened to have a blood type that protected me against malaria as is the case with carriers of the gene for sickle cell or thalassemia, I wouldn’t want to move to a place where malaria was rife, unless I had another good reason to go.
Anyway, the straight answer to the question is that yes, certain blood types have a different risk associated with specific diseases and that in terms of ancestry these blood types tend to be associated with particular regions. As I said, it seems that being a carrier of the sickle cell gene provides some protection against malaria and the same too for thalassemia. On a related note, other “diseases” are associated with reduced risk of specific infection. Carriers of the cystic fibrosis gene (not a blood type, obviously), for instance, have a lower chance of suffering from typhoid and cholera.
Sciencebase readers might be able to shed a little more light on the relationship between blood type and disease risk.