|MadSci Network: Genetics|
Hello Jackson, The ABO system and the Rh system of blood typing refer to specific types of sugar (not like the sugar you find in candies but they are sugars nonetheless) that are present on the proteins expressed on the surface of your red blood cells. These proteins are called glycoproteins (glyco means sugar) and they represent targets for the immune system. Your immune system is accustomed to your specific glycoprotein expression. That is why your immune system do not react against your blood cells. If, however, you receive blood that do not match your blood type, the received red blood cells will express a different pattern of glycoproteins and your immune system will try to destroy them as they are viewed as "different" and maybe harmful to you, much like a bacteria. You have 23 pairs of chromosomes. On one specific pair of chromosome is found the gene responsible for determining your blood type. You can have the A or B gene responsible for the expression of the glycoproteins "A" or "B" or you can have no gene (which is represented by O) . Since you have two chromosomes in that pair and one came from your mother and the other from your father, your blood type will come from a combination of possibilities. For the ABO system, there are six possibilities. You can be AO or AA (blood type A), BO or BB (blood type B), OO (blood type O) or AB (blood type AB). For example if your mother and father are really of blood type A, they could be either AA or AO themselves, which mean that they could not have had an AB child like you (see examples at the end of the answer). They would have had children of type A or O only. Don't panic though! This could easily be a mistyping of their blood or yours or it could be that they think they are of A type while they are not really (one of them is probably B or AB). As for the Rh antigen, it is another type of sugar and it refers to the RhD antigen. Two other Rh antigens exists, the Rhc/C and Rhe/E antigens. So it appears that you are AB+ (which means you are of blood type AB and express RhD on your cells) and you also are Rhc positive. If your husband is not Rhc positive (80% of men are Rhc positive but he has a 20% chance of being either RhC or Rhe/E) then your child could express an antigen that is different of yours and thus be recognized as "different" so that your immune system would attack it and your body would thus reject it. This condition can be treated (normally) so ask your doctor if this could have been prevented with medication. Finally, here is an interesting web site on blood type and pregnancy problems. http://www.med.unc.edu/obgyn/MaternalFetalMedicine/RHdisease.html I hope this answered some of your questions, Ciao! Mike Here is a checker board using Mendel genetics that can help figure out your blood type. Examples A female that is of blood type AB mate with a male of blood type A (AO); their offspring would have 50% chance of having blood type A, 25% chance of being blood type B, and 25% of being blood type AB Female A B A AA AB Male O AO BO A female of blood type B (BO) mate with a male of blood type A (AA); their offspring would have 50% chance of having blood type AB and 50% chance of being blood type A. Female B O A AB AO Male A AB AO
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