Genetics Study Guide
Name: ___________________________
Please complete this study guide to prepare yourself for the test tomorrow!!
Vocabulary Term
1) Trait
2) Homozygous
3) Dominant
4) Codominance
5) Phenotype
6) Polygenic Trait
7) Allele
8) Pure-breed
9) Law of Independent
Assortment
10) Gregor Mendel
11) P Generation
12) Recessive
13) Hybrid
14) Law of Segregation
15) Genotype
16) F1 Generation
17) Heterozygous
18) Sex-Linked Trait
19) Multiple Alleles
20) Incomplete
Dominance
Quick Description in your own words!
In the following pedigree, the shaded shapes represent people that have Huntington’s Disease.
This is an autosomal recessive trait. Healthy (H) is dominant over huntingtons (h).
21) Fill in all the genotypes on the pedigree below (including unknowns!)
C
K
D
L
E
M
A
B
F
G
N
H
I
J
O
22) How many generations are present in this pedigree?
23) How G related to E?
24) If studly Man E married a woman that is heterozygous for Huntington’s disease, what percentage
of their offspring would have Huntington’s Disease?
25) Physical symptoms of Huntington’s Disease typically begin in the mid-40’s to early 50’s. How
would the pedigree be different if it was for a recessive disease that killed people by age 2?
(Think!)
26) Examine the following pedigree chart of color-blindness. In humans, color blindness is caused
by a recessive X-linked allele. On the diagram, label the genotypes of the individuals 1-16. (List both
if there are two possible genotypes)
27) In a certain species of dog, a black nose (B) is dominant over a pink nose (b). Predict the
genotypes and phenotypes produced by crossing a cute, pink-nosed male dog and a female with a
heterozygous, wet nose.
(I
dog noses!)
28) Poinsettias are available in three colors because they demonstrate incomplete dominance. This
beautiful flower can be red (R), white (W), or a unique heterozygous plant. Set up a Punnett Square
that demonstrates the cross between each of the following combinations:
a. red (RR) x white (WW)
List the possible genotypes & describe the phenotypes from the cross?
b. A white plant crosses with a heterozygous poinsettia plant.
What are the possible genotypes & phenotypes from the cross?
29) In horses, gray horses (G) are codominant to white horses (g). The heterozygous horses (Gg) are
called appaloosa horses. Cross a white horse with an appaloosa horse and predict the phenotypes of the
offspring.
What do you think an appaloosa horse looks like?
31) Fruit fly eye color is a sex-linked trait on the X chromosome. Red eyes (R) is dominant over
white eyes (r) in this type of fly. Show the cross of a red eyed female (heterozygous) and a red eyed
male. What are the genotypes of the parents? →
X X
&
X Y
How many are:
white eyed males?
white eyed females?
red eyed males?
red eyed females?
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