Blood groups in humans are characterized by the presence of antigens (specifically, glycoproteins) on the surface of red blood c
ells. The ABO blood group is controlled by three alleles of a single gene on chromosome 9: and B are codominant, and both are dominant to į, The MN blood group is controlled by gene L on chromosome 4. The gene has two codominant alleles, LM and L^N. Rh is the most complex of the blood group types, involving at least 45 different antigens. The most clinically important antigen, D or Rho, is encoded by the gene RhD. which is found on chromosome 1. Individuals that are Rh-positive have either one or two RhD. genes, whereas the Rh-negative phenotype is caused by the absence of the RhR gene. (The antithetical allele d does not exist, however the letter "d" is used to indicate the D-negative phenotype).
Four babies born on the same day were accidentally mixed up in a maternity ward. Given the following blood types, can you match each baby to its correct set of parents.
BLOOD TYPES
BABY COUPLE
a. O, MN, Rh* 1. O, MN, Rh x B, N, Rh¯
b. AB, MN, Rh* 2. A, M, Rh* x B, M, Rh*
c. O, M, Rh- 3. A, M, Rh* x A, N, Rh
d. B, N, Rh 4. A MN, Rh x AB, M, Rh*
