Name: _____________________________________________Date:____________ Period:____
Human Traits Genetics Activity
The following are considered by many to be single-gene traits, which mean that there are two alleles
(versions of a gene) for a trait. It is important to note that scientists are researching the human genome and
what was once considered to be a single-gene trait may in fact be a trait controlled by multiple genes, such
as skin color.
Find out if your traits are dominant or recessive and plot them on your genetic wheel.
Activity:
1. In this activity, we will examine our own bodies for the presence of simple traits by examining our
phenotypes (what we look like); then we will approximate our genotypes (what our DNA codes for) by
comparing our observations to a chart of physical characteristics on a Traits Table.
2. Using the Traits Table below (it continues onto the next page), put an “X” next to the phenotype that
best describes you for 7 different characteristics.
3. To find your number, follow the directions to shade in the page with the Genetics Wheel to find your
corresponding number. These 7 characteristics can be put together into 128 different combinations!
Traits Table
Trait
1. Laugh dimples
2. Tongue roll
3. Crossing thumbs
4. Many freckles
Phenotype
Dimples appear in cheeks while
smiling/laughing
“X”
Genotype
L_
No dimples
ll
Can roll tongue into a “U” shape
T_
Cannot roll tongue
tt
Left thumb on top of clasped hands
C_
Right thumb on top of clasped hands
cc
Many freckles present on face
M_
No/very few freckles on face
mm
Traits Table, continued
Trait
5. Ear lobes
6. Widow’s peak
7. Blue eyes
Phenotype
Detached ear lobe
“X”
Genotype
E_
Attached ear lobe
ee
Peak in center of hairline
W_
No peak in center of hairline
ww
Any color besides blue
B_
Blue eyes
bb
On the next page, use the Genetics Wheel to determine which combination number you are.
Genetics Wheel
Begin in the center of the wheel with the “L” and “ll” expressions for hair color. Use the Traits
Table to find what the letter symbols indicate on the wheel, then shade in your genotype (Note: If you are a
dominant genotype, you will shade in the capitol letter since we know you must carry at least one gene that
is dominant. If you have a recessive phenotype, you will shade in the two lowercase letters to represent
your genotype).
After you start in the middle, you have to make sure you move outwards on the circle, shading
sections that directly connect to the last region you shaded so it forms a continuous “map” that leads to a
number on the outer circle.
Follow-Up Questions (Please answer with complete sentences):
1. What is your Genetics Wheel number? ____________ We are going to share out our numbers in
class to determine if anyone shares numbers. Does anyone else in class have your exact number?
If so, how many other people? If not, why don’t you think so?
2. If more genetic traits were included in the wheel, would it be more likely or less likely that more
people in class would share your number? Explain your answer.
3. Look at the Wheel. How does a person with combination 63 differ from someone with the
combination 61?
4. We all inherit traits that come from each of our parents. If you have a recessive trait, like
no/very few freckles, it means you inherited a recessive gene from each parent. If you have
many freckles, it means that you inherited AT LEAST one dominant gene. That means that
someone with many freckles COULD be FF or Ff since a dominant trait complete takes over,
even if that person inherits a recessive gene from one parent. On the wheel, we show this as D _
since we do not know whether people with dominant traits are DD or Dd just by looking at them.
Do you think that all “dominant” traits are more common in a population of people? Give an
example. Hint: Do most people in the class have many freckles?
5. In a complete sentence or two, please explain one specific thing you learned about genetics in
this activity. (You cannot just write “I learned about genetics.” Be specific!!)