Blood Groups and Compatibility

Blood groups are named after ABO method.

ABO type is related to the three alleles of the gene , i ,A, B.
ii gives type O. AA, Ai gives A. BB, Bi gives B. AB gives AB.

Rh factor:
Rhesus factor or (Rh factor indicated by + or -) is named after Rhesus Monkey, first known in 1940 in Rhesus Monkey :-). Rh factor is present in the surface of red blood cells. Rh+ positive donor is a mismatch for the Rh- recipient of the same group.The converse, i. e. if there is Rh- donor and Rh+ recipient from the same group, is acceptable.
( Note: The current research is being done to make all groups compatible to each other)

Below is the table of donor and recipient type of all Blood Groups ( X means compatiblity).