Question

A type A woman is the daughter of a type O father and type A mother. If she has children with a type AB man, what is the probability that their first and second children are AB blood type?

Group of answer choices

1/32

1/4

1/16

1/64

Answer 1

there are three alleles at the ABO locus which determine the blood type, IA, IB and i.

IAIA, IAi- A type blood

IBIB, IBi- B type blood

IAIB- AB type blood

ii- O type blood

The woman has A-type blood and her father has O type blood, which means she has inherited i allele from the father, so her genotype is IAi.

Man has AB type blood so his genotype is IAIB.

IAi * IAIB

	IA	i
IA	IAIA ( A-type blood)	IAi ( A-type blood)
IB	IAIB ( AB type blood)	IBi ( B type blood)

probability of getting a child with AB type blood= number of children with AB type blood/total number of progeny=1/4

probability that their first and second children are AB blood type = (probability of getting a child with AB type blood)^2=(1/4)^2=1/16