Download For the Fieldwork Assignment, you must observe FIVE traits in

1. Earlobes (Attached/Free)
Look at the lower part of the ear at the lobe. Is the lobe attached directly to the head or is it unattached (free)
from the head?
Photo c1 below shows the free ear lobe while photo c2 shows the attached. The dominant gene results in a
free/unattached ear lobe. The attached lobe is a manifestation of two recessive genes.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission
2. Hitchhiker's Thumb
Observe your thumb. If it will naturally bend backwards approaching a 45 degree angle, you have hitchhiker's
thumb. Hitchhikers thumb is the result of being homozygous recessive. There may be various degrees of the angle
that is exhibited. For the purposes of this exercise, the angle should be approaching 45 degrees. Those whose
thumb will not bend to this degree will be considered as having the dominant gene
.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission
3. Hallux Length (Big Toe)
The big toe is also called the hallux. The dominant trait is to have the hallux shorter in comparison to the 2nd toe.
When the big toe is longer than the 2nd toe, this is a manifestation of the homozygous recessive.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission
4. Dimples
The inheritance of cheek dimples is a manifestation of a dominant gene. If you have no dimples, this is the
homozygous recessive trait.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission
5. Tongue Rolling
Try to roll your tongue as in the picture below. Roll it so that the sides of the tongue curl upwards. Those who can
roll their tongue have the dominant gene.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission
6. Bent Little Finger
This characteristic is noted by the terminal (tip end) bone of the little finger angling toward the 4th (ring) finger
rather than going straight. This is a dominant trait and the straight little finger is a homozygous recessive trait.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission
7. Widow's Peak
Pull your hair back off of your forehead. If you have a noticeable downward point in the center of the forehead,
you have what is known as a widow's peak. Those who have a widow's peak have the dominant gene. If the
individual is bald, this trait will be masked so it will not be determined.
Photo: Copyright 1985 Carolina
Biological Supply Company,
Reprinted by permission