Question

Ellie May, a mother with type B blood, has a child with type O blood. She claims that Jethro, who has type A blood, is the father. He claims that he cannot possibly be the father. Further, blood tests ordered by the judge reveal that the father is homozygous. The judge rules that:

a) Ellie May is right and Jethro must pay up.

b) Jethro is right and is a winner-winner (chicken dinner).

c) Ellie May cannot be the real mother of the child. There must have been an error made at the hospital.

d) It is impossible to reach a decision based on the limited data available.

e) none of these are correct.

can you show work using the punnet square, thank you.

Answer 1

Question:

Ans: b Jethro is not the father

Mother is B blood group

Genotype combination of mother will be : BO, BB she can pass either allele B or O to the child

The father in question have A blood group but homozygous

Therefore his genotype will be : AA

If mother is homozygous AA and father Is BB only possible blood group of the child will be AB

Parents: AA X BB

child: AB

On computing punnet square

	A	A
B	AB	AB
B	AB	AB

On computig punnet square assuming mother is Heterozygous BO

	A	A
B	AB	AB
O	AO	AO

Therefor only possible blood group of child will be AB or A

Explanation of Blood Groups:

There are three type of allele determining blood group in humas along with thr Rh factor

Allele A, B, O. Rh factor can either be postive or negative in an individual

for these three type of allele different types of genotypic combinations are possible.

Genotypic combination: (A) (B) (O) -----------> AA, AO, BB, BO , OO , AB

• A and B are completely dominant over O , therefor AO and BO are usually termed A blood group & B group respectively.
• A and B exhibit co dominance.None of them will be dominant over other. Both of them will be expressed when they come together.

Phenotype of different genotypes are

AO,AA : A blood group

BO, BB : B blood group

OO : O blood group

AB : AB blood group

Each allele in a combination will be inherited from the parents, one from the mother and other from the father contribute the blood group type of the infant.

On computing the punnet square for different blood groups these are the possible outcomes for all the combiantion.

	F A T H E R' S
M O T H E R' S		A	B	AB	O	C H I L D' S
A	A or O	A,B,AB,O	A,B,AB	A or O
B	A, B,AB, O	B or O	A,B,AB	B or O
AB	A,B, AB	A,B,AB	A,B,AB	A or B
O	A or O	B,O	A or B	O