Biology- Ms Nguyen
Inheritance Patterns Worksheet
PART 1
NAME: ________________________
PERIOD: ___________
DATE: _____________
_______
15
_____________________________________________________________________________________
Answer the following questions.
1) In humans, dimples are inherited as a dominant trait. A man heterozygous for dimples marries a
woman without dimples. (2 pts)
a) What are the genotypes of the couple?
Father’s genotype: ___________________
Mother’s genotype: ___________________
b) What proportion of their children will have dimples? Show the Punnett square used to solve
this. (2 pts)
Proportion = _______ dimples : _______ w/o dimples
2) In guinea pigs, the allele for black fur (B) is dominant over the allele for white fur (b). A black
male guinea pig is mated to a white female guinea pig. The offspring were 7 black and 6 white
guinea pigs. Based on the results of the two possible testcrosses, what are the genotypes of the
parents? Show both testcrosses used to solve this problem. (4 pts)
Father’s genotype: ___________________
Mother’s genotype: ___________________
3) A brown mouse is mated to a white mouse and all of their offspring are brown.
a) What are the genotypes of each of the mice that were crossed? (2 pts)
Brown mouse: __________________ White mouse: _____________________
b) If two of the brown offspring were mated together, what percentage of the F2 mice would be
brown? Show the Punnett square used to solve this. (2 pts)
Percentage: __________% brown
4) In tomatoes, red fruit (R) is dominant to yellow fruit (r). A true breeding red-fruited plant is
bred to a true-breeding yellow-fruited plant.
a) What phenotypic ratio would you expect to see in the F1 offspring? (1 pt)
b) If two of the F1 plants were bred, what phenotypic ratio would you expect to see in the F2
offspring? (1 pt)
c) What genotypic ratio would you expect to see in the F2 offspring? (1 pt)
Biology- Ms Nguyen
Inheritance Patterns Worksheet
PART 2
NAME: ________________________
PERIOD: ___________
DATE: _____________
_______
22
_____________________________________________________________________________________
Answer the following questions.
1) In fruit flies, curly wings (c) is recessive to straight wings (C). Ebony body (e) is recessive to
tan body (E). Suppose you had a male fly that had curly wings and was heterozygous for
body color and a female fly that was heterozygous for wing type and had had an ebony body.
a. What is the genotype for the male fly? (1 pt)
b. What type of gametes could the male fly produce? (1 pt)
c. What is the genotype for the female fly? (1 pt)
d. What type of gametes could the female fly produce? (1 pt)
e. Construct a Punnett Square to determine the PHENOTYPIC ratio that you would
expect to find in the offspring of these two flies. What is the phenotypic ratio? (2 pts)
Phenotypic Ratio: ___________________________________________________________
2) Both individuals of a recently married couple are heterozygous for cystic fibrosis, a recessive
genetic disorder. They would like to start a family and would like to have two children.
a. What is the probability that their first pregnancy would result in a child with cystic
fibrosis? (1 pt)
b. What is the probability that their second pregnancy would result in a child with cystic
fibrosis? (1 pt)
3) Dwight and Angela both have freckles, but their son Michael does not. Show with a Punnett
square how this is possible. If Dwight and Angela have another child, what is the probability
that it will have freckles? (2 pts)
Proportion = _______ freckles : _______ w/o freckles
4) In shorthorn cattle, the heterozygous condition of the alleles for red coat color (CR) and
white coat color (CW) is a sandy color called roan. If two cattle with roan coats are mated,
what phenotypic ratio of offspring will be produced? (2 pts)
Proportion: ___________________________________________________________
5) Gloria is type A blood and Jay is type B blood. Their son has type O blood.
a. What are Gloria’s and Jay’s genotypes? (2 pt)
b. Is it possible for their next child to have type AB blood? (1 pt)
c. Is it possible for any of their children to have type A blood? (1 pt)
6) Marge has type O blood and Homer has type AB blood.
a. Can they have a child with Marge’s blood type? (1 pt)
b. Can they have a child with Homer’s blood type? (1 pt)
c. What is the phenotypic ratio of their children’s blood? (1 pt)
7) Colorblindness is a sex-linked trait in humans. Both Kanye and Kim have normal colorvision.
After 10 years of marriage, Kim gives birth to a colorblind son. Kanye filed for divorce,
claiming he’s not the father of the child.
a. Is Kanye justified in his claim for nonpaternity? Explain why. (2 pts)
b. Circle the correct answer(s). From which grandparent could the son have inherited
his X chromosome? More than one answer may be correct. (1 pt)
A. Kim’s Mom
B. Kim’s Dad
C. Kanye’s Mom
D. Kanye’s Dad