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Name ______________________
Non-Mendelian Inheritance Practice Problems
Be sure to make dominant and recessive alleles clearly distinguishable. Punnett squares should
show genotypes and phenotypes. Make Punnett squares only as big as needed to show ratios.
Draw Punnett squares here
1. Skin color in humans is determined by a polygenic
inheritance system, possibly involving involving as many
as 9 genes. For simplicity let’s consider the influence of
3 genes: A, B, and C, where the dominant allele darkens
skin color. Suppose a women who is AABbCc mates
with a man who is AaBbcc.
A. List all of the possible genotypes of the gametes that
could be produced by each the parents?
: ______________ : _______________
B. Draw a Punnett square that shows the genotypes
possible, and number each genotype from lightest (1) to
darkest skin coloration.
C. In this cross, how many dominant alleles will children
with the darkest skin coloration possess, and what
theoretical fraction of the children will have this
coloration?
# of alleles: ____
fraction: _____
2. Mrs. Eryth is carrier of the sex-linked hemophilia allele, and Mr.
Eryth is normal (as far as blood chemistry goes).
A. Draw a Punnet square that shows the theoretical genotypes and
phenotypes among their children.
B. They actually have 4 male and 4 female children; how many of
each sex would be expected to be hemophiliacs, carriers, and
normal?
# hemophiliac
#carrier
# normal
:
_____
_____
_____
:
_____
_____
_____
C. Is it more likely that Mrs. Eryth obtained the hemophilia allele
from her mother or father? Why?
3. In humans, the alleles for blood type are designated IA (A-type
blood), IB (B-type blood) and i (O-type blood). What are the expected
frequencies of phenotypes in the following matings? Draw a Punnett
square showing the results for a).
%A
%B
%O
%AB
a) heter A x heter B :
____
____
____
____
b) IAIB x IAi :
____
____
____
____
c) IAIA x IBIB :
____
____
____
____
d) AB x O :
____
____
____
____
1. In rabbits, white fur color (W) is dominant to black, and long ears (L) are dominant to short. Draw a
Punnett square that represents the cross between two rabbits heterozygous for both traits. What are the
phenotype and genotype ratios?
2. In humans, polydactylism (having an extra finger on each hand) is dominant to the typical 5-finger
arrangement. Tongue rolling is dominant to not being able to roll one’s tongue. A man who is
homozygous for 5-fingers and who cannot roll their tongue has children with a woman who is
heterozygous for polydactylism and tongue rolling. Draw a Punnett square that represents the cross.
What is the probability the couple will produce a polydactyl baby who cannot roll their tongue?
3. A species of bird is threatened with extinction because its habitat is being destroyed by deforestation.
As a research ecologist, you have been chosen to ensure the genetic diversity of the species. In this
species of bird, feathers may be white, black, or white with black spots. In the same species, beaks may
be long, medium or short. A black bird with a medium beak pairs with a spotted bird with a long beak.
Draw a Punnett square that represents the cross. Make a list of all of the phenotype combinations this
pair could possibly produce.
The expected phenotypic ratio of the progeny of a SsYy x ssyy test cross is:
A. 9:3:3:1
B. 3:1
C. 1:1:1:1
D. 1:2:1
E. 3:1:1:3
Blood Type Practice questions
Be sure to use proper designation of alleles (IA, IB or i) where called for
This will not be collected
I. Identify the Characteristics of the Different Blood Groups
Blood
group
A
B
O
AB
Type(s) of
antigen on cells
________
________
________
________
Type(s) of
antibody in serum
____________
____________
____________
____________
Remember: possible antigens are ‘A’ and ‘B ‘
Remember: antibodies are ‘anti-A’ or ‘Anti-B’
Which blood groups are considered the "universal donor" and "universal recipient?"
Explain why these blood groups are so designated
II. Identify the characteristics of the Alleles for Blood Type Determination
Allele Expression
This allele creates
Allele
(CoDom or Rec)
which antigen on cell
IA
_____
______
B
I
_____
______
i
_____
______
III. Identify the Genetics of Blood Type Determination
What are the possible genotypes
Blood type
of persons with this blood type
A
____________________
B
____________________
AB
____________________
O
____________________