Non-Mendelian Genetics

Question

In humans, there are three alleles for blood types, A=IA, B=IB, and O=i. Type A and B are co-dominant alleles and type O is recessive. Could a man with type AB blood be the father of a child with type O blood if the mother was heterozygous for type A blood?

In four-o'clock flowers red petals are incompletely dominant over white petals, producing pink petal flowers in the heterozygous stage. What would be the probability of having white offspring if two pink flowered plants were crossed?

Answer 1

For the first question, no, the cross would be I(A) I(B) x I(A) i(O),

so you'd get a genotypic ratio of 25% each I(A) I(A) homozygous A, I(A) i(O) heterozygous A, I(A) I (B) codominant AB, and I(B) i(O) heterozygous B,

leading to a phenotypic ratio of 50% A, 25%AB, and 25% B

The second question is like a typical heterozygous cross, so there is a 25% chance of white

that is RW x RW yields 1:2:1 RR:RW:WW