1. Madison has type A blood, and so does her sister Abi. Her sister Marley has type O blood. A. What are Madison's parents' blood types? B. What is the genotype of Madison's blood?

A) Madison’s parents’ blood types may be either A & 0, or A & A.

B) Depending on her parents’ genotypes, Madison’s genotype may be either AA or A0

Explanation:

Since the A allele is dominant with respect to the 0, a person with blood type A may have either one (A0 genotype) or two A alleles (AA genotype). In contrast, a person with blood type 0 may only have two 0 alleles (00 genotype).

Because one of the sisters has type 0 blood, we have to assume that both of her parents have at least one 0 allele. There are two situations which may give rise to the described scenario (see Punnett squares):

Alternative 1: One of the parents has A blood type (A0 genotype), and the other has 0 blood type (00 genotype). Madison’s genotype may only be A0.

| 0 | 0

——————————

A | A0 | A0

——————————

0 | 00 | 00

Alternative 2: Both parents have A blood type and A0 genotypes. Madison’s genotype may be either A0 (probability of 2/3) or AA (probability of 1/3).

| A | 0

——————————

A | AA | A0

——————————

0 | 0A | 00

c.) polymerase chain reaction

- "unlike the original dna fingerprinting method, dna profiling does not use restriction enzymes to cut the dna. instead it uses the polymerase chain reaction (pcr)? to produce many copies of specific str sequences. pcr is an automated procedure that generates lots of copies of a specific sequence of dna."