Download Pedigrees and Combining Probabilities

Pedigrees and Combining Probabilities
1.
a) In this family, individuals III-5 and III-6 share a grandmother who was a carrier for a genetic
disorder. How is this disorder inherited?
b) Individuals III-5 and III-6 are phenotypically normal. Assuming that everyone who has married
into the family is homozygous normal, what are the chances that individual III-5 and III-6 will
have a child affected with this disorder?
2.
a) How is this disorder inherited?
b) What is the probability that individual II-2 is a carrier?
c) What is the probability that individual III-4 is a carrier?
Pedigrees and Combining Probabilities
3.
a) This pedigree shows the inheritance of a rare autosomal recessive trait. Calculate the probability that
individual III-1 and individual III-2 will have a child affected by this disorder.
b) What would be the probability if the trait were inherited as a sex-linked recessive trait?
4.
a) How is this disorder inherited?
b) What is the probability that that individual III-2 and III-3 will have a child affected by this disorder?
c) What is the probability that individual II-3 is heterozygous for this disorder?
d) What is the probability that individual III-7 is heterozygous for this trait?
Pedigrees and Combining Probabilities
I
II
III
The pedigree above illustrates the inheritance of a certain genetic disorder within a family.
A. Identify the pattern of inheritance illustrated by this pedigree. Explain how you know
this.
B. Pick one person in the pedigree and give their genotype. Explain how you know this.
C. Pick one unaffected female in Generation III. Tell that person’s probability of being a
carrier of this disorder. Explain how you know this.