Question

Tilly's mother has the blood type AA and their father has the blood type BB.

Which blood type could Tilly have?
Draw a Punnett square on scratch paper if needed!
Phenotypes and Genotypes of Blood Types
Blood Type and Allele
A (IA)
B (1³)
AB (IA IB)
O (I)
Possible Genotypes and Alleles
AA or AO (I^I^ or I^I)
BB or BO (1B1B or IBI)
AB (I^ IB)
00 (II)
AA
BB
AB
AO

Answer 1

Tilly could have blood type A, B, or AB.

Tilly's mother has blood type A, which means she must have the genotype AA or AO. Tilly's father has blood type B, which means he must have the genotype BB or BO.

When Tilly's parents' genes combine, there are three possible outcomes:

One possible outcome is IA from the mother and I^B from the father, resulting in the genotype I^IB, which is blood type AB. Another possible outcome is IA from the mother and I from the father, resulting in the genotype I^I, which is blood type A.

The last possible outcome is I from the mother and I^B from the father, resulting in the genotype AO, which is also blood type A.

In conclusion, Tilly can have blood type A, B, or AB.