Why Do We Have Blood Types?

Knowing your blood types can be a matter of life and death. So you might think that scientists had a clear idea of why we have them in the first place. I’ve written a feature for Mosaic, a new online magazine about medicine, in which I try to get the answer. It proves a lot harder than I expected. Check it out.

10 thoughts on “Why Do We Have Blood Types?

  1. You could look into the Duffy blood group. When people are educated in blood banking, they usually run into charts indicating the previlance of particular antigens in different populations. A large portion of caucasians have Duffy, but it is far less common in people of recent african descent (IE people who’s ancestors didn’t migrate out to form the european, asiatic and “races”). The more lethal species of the Malarial parasites use these antigens as entry points into red blood cells, while lacking them doesn’t make one immune, it seems to reduce the risk of getting a clinical case of malaria.

  2. Having blood type is the quickest way to save a life in case of accident and also in marriage ur blood type will determine if couples are compatable for marriage after kmowing eachother blood type.

  3. You seem to miss a lot of other bloodtypes other than AB and Rh (Kell, Kidd, Lutheran, Dufffy, MNSs…). See table 4.1 in Mielke, Konigsberg & Relethford’s “Human biological variation” (2006, OUP).

    They also offer a plausible explanation (different bloodtypes offer some protection against colonization by pathogens and parasites for which blood cell proteins act as a receptor) for the existence of different blood groups.

  4. Doesn’t blood group types signify different time periods of human evolution ,from hunter gatherer O type ,to A type ,the first cultivators /grain eaters ,signifying first farming communities and civilizations. Then B type ,the Nomadic type ,the Dairy eaters ,then and lastly AB type ,the combination or spread of nomadic tribes into new territory creating hybrid blood type AB .Gave rise to the Blood group diet

    [CZ: As I explain in my story, this is a widespread impression about blood types that the current scientific evidence does not support.]

  5. Excellent article. One of the most exciting revelations of the flood of genomics data is the extent of diversity in the human genome. Blood types provide the classic example of the fact that we, as a species, have variation in many if not most protein coding sequences, and these have functional consequences. The new data about the causes of the spectrum of diseases we still call autism and schizophrenia provide another example. Some of this variation is the result of new loss-of-function mutations that will be under negative, purifying selection while other variation has selective advantage, at least in some environments. Blood types led the way in that regard.

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