Inheritance
The D antigen is inherited as one gene (RHD) (on the short arm of the first chromosome, p36.13-p34.3) with various alleles. Though very much simplified, one can think of alleles that are positive or negative for the D antigen. The gene codes for the RhD protein on the red cell membrane. D- individuals who lack a functional RHD gene do not produce the D antigen, and may be immunized by D+ blood.
The epitopes for the next 4 most common Rh antigens, C, c, E and e are expressed on the highly similar RhCE protein that is genetically encoded in the RHCE gene, also cound on chromosome 1. It has been shown that the RHD gene arose by duplication of the RHCE gene during primate evolution. Mice have just one RH gene.
The RHAG gene, responsible for encoding Rh-associated glycoprotein (RhAG) is found on chromosome 6a.
The polypeptides produced from the RHD and RHCE genes form a complex on the red blood cell membrane with the Rh-associated glycoprotein.
Read more about this topic: Rh Blood Group System
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