Download Genetics Review Worksheet

Name: ________________________________________________ Date: ______________ Period: _______
Genetics Review Worksheet
1) From your Punnett Square above, cross the four possible outcomes with another healthy carrier (Ff). Assume autosomal
recessiveness.
a.
From all four Punnett Squares, circle all the homozygous recessive possibilities.
b.
From all four Punnett Squares, shade in all the homozygous dominant possibilities.
2) PKU is an autosomal recessive genetically transmitted condition that can ultimately lead to brain damage. Persons who
are heterozygous are healthy even though they carry the PKU allele. Persons who are homozygous recessive have the
disease. Cross a heterozygous carrier with a person who has PKU. Show your results below.
What is the probability of getting a:
a.
Homozygous dominant offspring? __________
b.
Homozygous recessive offspring? __________
c.
Carrier offspring? __________
d.
Healthy offspring? _________
3) A research lab requires a supply of pure breeding freckled frogs (FF) for a cloning experiment. A lab assistant has a pet
frog with freckles but it's uncertain if it is homozygous dominant (FF) or heterozygous (Ff). The pet frog is crossed with a
homozygous recessive smooth (non-freckled) frog (ff). Half of the offspring are freckled frogs and half are smooth.
Option 1: FF x ff
Option 2: Ff x ff
From the results described in the problem, what is the genotype of the lab assistant’s frog? Explain your reasoning._________________________________________________________________________________________________________
_________________________________________________________________________________________________________
4) Cystic fibrosis is an autosomal recessive genetically transmitted condition in which the body produces excess mucus that
clogs the lungs and intestines. Martin and Audrey were married a few years ago. Even though Martin has cystic fibrosis,
only their 4th and youngest child Joann suffers from the disorder. Audrey’s mother comes from a family with no history of
CF. Audrey’s father was healthy even though his mother was a victim of cystic fibrosis. Martin’s mother and father were
both healthy. In area A, complete a pedigree and fill in the genotypes for everyone mentioned or referred to. In area B,
complete a Punnett Square for Martin and Audrey and answer the probability questions.
Hint: You should be able to figure out the complete genotypes for 11 people over the course of 4 generations.
Area A
Area B
a.
What is the probability
of having a child with
CF?
b.
What were the odds
that the other 3
children would all be
healthy?
SEX-LINKED PUNNETT SQUARES
5) Hemophilia is a recessive disorder found on the X chromosome of males and females. Patricia is a healthy carrier of
hemophilia and Sam is completely healthy. Complete the Punnett square below.
a.
List the phenotypes of the F1 generation.
__________________________________________________________
What is the probability of getting:
b.
Daughter with hemophilia? ___________________________________
c.
Son with hemophilia? ________________________________________
d.
Carrier? ___________________________________________________
e.
Healthy child? ______________________________________________
f.
Two children both with hemophilia? ____________________________
6) Colorblindness is a recessive disorder found on the X chromosome of males and females. Judy is homozygous recessive
for colorblindness and Dennis is healthy. Complete their Punnett square below.
a.
List the phenotypes of the F1 generation.
__________________________________________________________
What is the probability of getting:
b.
Colorblind daughter? ________________________________________
c.
Color blind son? ____________________________________________
d.
Child that carries the color blind allele? __________________________
e.
Heterozygous child? _________________________________________