Dr. Paul is blood type O. His father was blood type A and his mother was blood type B. What were the genotypes of his parents and what are the possible blood types and ratios expected for crosses involving these parental genotypes?
2 answers
Dr. Paul must have received an O gene from each parent, but they also had A (dad) and B (mom) genes. That should give you their genotypes. Using a Punnett square should answer your last question. (See one of SraJMcGin's sources.)
a