# Question: 1. Two parents with blood types A and B have a child who has O blood type. What is the...

## Question:

Question: 1. Two parents with blood types A and B have a child who has O blood type. What is the chance that their next child will be A?

A. 0

B. 1/2

C. 1/4

D. 1

Question: 2. Hairy ears is a Y-linked trait. Suppose a hairy-eared man and a normal-eared woman have a daughter named Lucinda. Assuming 100% penetrance, what is the probability that Lucinda will have hairy ears?

A. 0

B. 1/4

C. 1/2

D. 3/4

E. 1

## Alternative Patterns of Inheritance

Many traits seen in nature follow a normal Mendelian inheritance pattern where there are 2 phenotypes, a dominant and recessive, and the trait is autosomal so males and females have equal chance of phenotypic ratios. However, there are also alternative patterns of inheritance like codominance, more than one equally dominant allele, and sex linked traits.

1. Two parents with blood types A and B have a child who has O blood type. What is the chance that their next child will be A?

Judging by the fact that parents with blood types A and B had a child with blood type O, they must both be heterozygous. Looking at the Punnet square below we can see that the chance of having a child with blood type A is 25%, or C: 1/4

i^A i^O
i^B i^A i^B i^B i^O
i^O i^A i^O i^O i^O

2. Hairy ears is a Y-linked trait. Suppose a hairy-eared man and a normal-eared woman have a daughter named Lucinda. Assuming 100% penetrance, what is the probability that Lucinda will have hairy ears?

This question does not even require a Punnet square in order to answer this. If the trait is Y-linked then it is only found in male offspring and since we are talking about a female daughter, there is no chance that she will the hairy ear trait.