S: Pedigree & Punnett Square
Human blood exhibits three different alleles. The A allele (I^) causes blood cells
to display the A antigen (A type blood). The B allele (I^) causes blood cells to
display the B antigen (B type blood). The A and B alleles exhibit codominance
such that heterozygotes will display both antigens (AB type blood). The
recessive allele (i) causes blood cells to display neither antigen (O type blood).
Suppose a mother with A type blood has a child with a father that has B type
blood. Both of the child's grandfathers have O type blood. Create a pedigree
showing the child, parents and grandparents. Figure out the possible genotypes
for the parents and grandparents. Complete a Punnett square to determine the
chances that the child will have A, B, AB or O type blood.