Name: _____________________________________Date:____________ Period:______
Genetic Wheel
Begin in the center of the wheel with the “L” and “ll” expressions for dimples. If you are
dominant and have the “L” you will be plotting your traits on the top half of the wheel. If
you are recessive, “ll”, you will be plotting your traits on the bottom half of the wheel.
Next, move to the tongue rolling exercise and mark whether you are dominant or
recessive. Continue plotting for each trait until you have reached the numbers on the
outside of that wheel. What is your number?__________
Human Traits
The following are considered by many to be single-gene traits- expressions of the two
alleles at one gene locus. 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.
Find out if your traits are dominant or recessive and plot them on your genetic wheel.
Laugh dimples:
ll
L
No dimples (homozygous recessive)
dimples (heterozygous or homozygous dominant)
Tongue roll:
tt
T
can’t roll tongue into a “U” shape (homozygous recessive)
can roll tongue into a “U” shape (heterozygous or homozygous dominant)
Crossing Thumbs:
cc
C
right thumb on top of clasped hands (homozygous recessive)
left thumb on top of clasped hands (heterozygous or homozygous dominant)
Many Freckles:
mm
M
no freckles (homozygous recessive)
freckles present on face (heterozygous or homozygous dominant)
Ear lobes:
ee
E
attached ear lobe(homozygous recessive)
free ear lobe (heterozygous or homozygous dominant)
Widow’s peak:
ww
W
no widow’s peak (homozygous recessive)
has a widow’s peak (heterozygous or homozygous dominant)
Blue eyes:
bb
B
blue eyes (homozygous recessive)
any other color eyes (heterozygous or homozygous dominant)