Download Biology: All Inheritance Patterns

Name: _______________________________________________ Date: ______________________ Period: ________
Biology: All Inheritance Patterns
Fill out the Punnett Squares & Pedigree Charts, while answering the following questions.
Autosomal Recessive Inheritance
1) Mendel noticed that when a tall plant and a short plant were crossed, all the offspring were tall in height.
Cross a heterozygous tall plant with a short plant. Complete the Punnett square below.
a. What are the genotypes of each parent? _______________
b. Which trait is dominant? ____________________________
What is the probability of getting a:
c. Tall pea plant? ________________
d. Heterozygous pea plant? _____________
e. Homozygous dominant plant? _____________
2) Phenylketonuria (PKU) is a recessive condition where sufferers lack an enzyme to break down tyrosine in their
diet. This condition, if left untreated, causes brain damage and retardation. Both Rita and Dexter are carriers of
this disorder and do not suffer from any symptoms. Complete the Punnett square and pedigree chart for all
mentioned in the story.
Draw your Punnett Square below
a. What are the phenotypes of each parent?
______________
What is the probability of getting:
b. Two healthy children?
_____________________________
c. A child who carries the disorder?
____________________
d. A child who has PKU? _______________________
e. A Homozygous recessive child?
______________________
Sex-Linked Inheritance
3) Hemophilia is a sex-linked recessive disorder found on the X chromosome of males (XY) and females (XX).
Marge is a healthy carrier of hemophilia and Homer is completely healthy. They have three children, Lisa, Bart,
and Maggie. Bart has hemophilia. Complete the Punnett square and pedigree chart for all mentioned in the story.
Draw your Punnett Square below
Draw your pedigree chart below
a. What is the genotype of Marge? ________ Homer? ________
What is the probability of :
b. Lisa and Maggie having hemophilia? _________________ d. Lisa/Maggie being carriers? ____________________
c. Having another son with hemophilia? _________________ e. Another healthy child? _______________________
4) Duchene Muscular Dystrophy (DMD) is a sex-linked recessive disorder where sufferers lack the protein called
dystrophin. Because sufferers lack this protein, their muscle cells wear away sooner than those unaffected
causing early death. Abby is homozygous recessive for DMD and Ray is healthy. Create a Punnett square and
pedigree chart for all mentioned in the story.
Draw your Punnett Square below
a. What is the genotype of Abby? _________
Ray? _________
What is the probability of getting:
b. A child with DMD? ______________
c. Girl with DMD? _____________
d. Homozygous child? ________________
If this couple has a boy, what are the chances that the boy will have DMD? _________________________________
Autosomal Dominant Inheritance
5) Huntington’s disease (HD) is a dominant disorder where only 1 copy of a defected allele will cause the sufferer
to lose brain function and eventually die. Russ and Leslie met at a HD support clinic and both contain the HD allele
and can expect a shortened life. However, they still want to know the chances of having a child without HD.
Can you help them? Create a Punnett square and pedigree chart for all mentioned in the story.
Draw your Punnett Square below
a. List the genotypes of each parent?
________________
What is the probability of getting:
b. A healthy child?
______________________________
c. A heterozygous child?
_________________________
d. A homozygous dominant child?
____________________
Incomplete Dominance Inheritance
6) With flower colors, how could one create all three colors at a time (red, pink, white)?
Prove your answer with a Punnett Square.
a. What is the phenotype of each parent? _______________
What is the probability of getting:
b. White flowers? ___________________________________
c. Homozygous dominant flowers? _____________________
d. Heterozygous flowers? _____________________________
e. Homozygous recessive flowers? ______________________
Codominant Inheritance
7) There are 3 alleles for blood (A, B, O). A and B are both dominant, and only O is recessive. Keva has
heterozygous type B blood and Kobe has type O blood. Complete the Punnett Square below.
a. What is Keva’s genotype? ________ Kobe’s? ________
What is the probability of getting:
b. The same genotype as Keva? ______________________
c. The same phenotype as Kobe? ______________________
d. A child with codominant blood? _____________________
e. A child with homozygous B blood? __________________
Dihybrid Punnett Square
8) Dihybrid crosses involve the inheritance of two different alleles.
If a male guinea pig that is heterozygous for short black fur mates
with a female guinea pig that is also heterozygous for short black
fur what traits will their offspring inherit?
Key:
B = Black fur b = brown fur
a. What is the male guinea pig’s genotype? ___________ Female? ___________
S = Short fur s = long fur
b. What are all the possible gamete combinations?
__________________________________________
c. List all the possible genotypes?
d. List all the possible phenotypes?
e. What is the phenotypic ratio? _____________________
f. What is the genotypic ratio? ___________________
Linkage Map
9) Suppose the cross-over frequencies for three gene pairs are: A to B = 7.5%, B to C = 10.5%, and A to C =
3%. Create a linkage map using the given information.
a. What is the order of these genes on a chromosome? _________________________________________________
b. Which genes are most likely to cross-over together? _____________________ Least likely? _________________
10) Use the cross-over frequencies given to draw a linkage map for the four genes listed. Think about the
relationship between the cross-over frequency and the distance in the linkage map units. Hint: Put gene “A” on
the far left of your map.
A to B = 20% B to C = 5%
A to C = 25%
A to D = 7%
D to B = 13%
D to C = 18%