Question

• Ms. Ritter has a problem. She claims that her

Answer 1

Answer:

Mrs. Ritter, whose blood type is B (Bi) is right in claiming that Ian - blood type A (Ai)- is the father of her baby, with blood type O (ii). Ex-boyfriend AB (AB) cannot be the father.

Explanation:

The blood type, according to the ABO system, is determined by the presence or absence of surface antigens A and B. In addition, genotypes can be co-dominant, in the case of A, B and AB, heterozygous (Ai or Bi) and recessive, in the case of group O (ii)

• Type A contains the antigen A and its genotype can be AA or Ai.
• Type B contains the antigen B, whose genotype can be BB or Bi.
• Type AB contains both antigens and a single genotype expression AB.
• Type O blood lacks surface antigens, its genotypic expression being ii.

According to this, to check if Mrs Ritter's baby is Ian's child, a crossing can be done:

♂ Ai

♀ Bi

Alleles       A       i

B              AB     Bi

i               Ai        ii

Ian and Mrs Ritter have a 25% chance of having a child with blood type O (ii), so the baby may be Ian's child.

To find out why the ex-boyfriend can't be the father

♂ AB

♀ Bi

Alleles       A        B

B              AB      BB

i                Ai       Bi

It is not possible that Mrs. Ritter's ex-boyfriend is the father of the baby, as the possible offspring in the crossover are A, B or AB.