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 / Phenotype / “X” / Genotype1. Laugh dimples / / Dimples appear in cheeks while smiling/laughing / L _
No dimples / l l
2. Tongue roll / / Can roll tongue into a “U” shape / T _
Cannot roll tongue / t t
3. Crossing thumbs / / Left thumb on top of clasped hands / C _
Right thumb on top of clasped hands / c c
4. Many freckles / / Many freckles present on face / M _
No/very few freckles on face / m m
Traits Table, continued
Trait / Phenotype / “X” / Genotype5. Ear lobes / / Detached ear lobe / E _
/ Attached ear lobe / e e
6. Widow’s peak / / Peak in center of hairline / W _
/ No peak in center of hairline / w w
7. Blue eyes / Any color besides blue / B _
Blue eyes / b b
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!!)