Name: __________________________________________________ Date: ___________________ Period: _______
Pedigree Sex-Linked Worksheet 3B (85% assignment) (10pts)
PROBLEM #1: This pedigree shows the typical inheritance pattern for Duchenne’s muscular dystrophy. Muscular dystrophy results
in muscle weakness, progressive deterioration of muscle tissue, and loss of coordination. People with Duchenne’s muscular dystrophy
rarely live past the age of 20. Use XD for the dominant allele, Xd for the recessive allele and Y for the male chromosome.
1.
How is Duchenne’s muscular dystrophy inherited? ________________
_________________________________________________________
2.
1
2
What are the genotypes of individuals # 1 & 2?
_________________________________________________________
3
3.
4
5
6
7
What are the genotypes of individuals # 3 & 4?
_________________________________________________________
4.
8
What are the genotypes of individuals # 10 & 11?
9
10
11
_________________________________________________________
5.
Suppose you are a genetics counselor. # 13 marries an unaffected male and seeks advice
from you as to whether or not they should have children. What would you advise and why?
12
13
14
15
_____________________________________________________________________________________________
_____________________________________________________________________________________________
PROBLEM #2: This pedigree shows the typical inheritance of hemophilia, a sex-linked recessive disorder. Because their blood does
not clot properly, people afflicted with hemophilia live to about 50 years old. Use XH for the dominant allele, Xh for the recessive
allele, and Y for the male chromosome.
1.
How is hemophilia inherited? ____________________________________
1
____________________________________________________________
2.
What are the genotypes of individuals # 2, 4, and 7?
#2 = __________
3.
#4 = __________
#7 = ___________
4
3
5
6
7
What are the genotypes of individuals # 3, 6, and 8?
#3 = __________
4.
2
#6 = __________
#8 = ___________
What is the probability that individual # 5 and an unaffected
8
9
10
11
male would have a son with hemophilia? _____________ What about have a daughter who is a carrier? _________
12
13