SOUTHWESTERN COLLEGE
School of Mathematics, Science & Engineering
Intro Molecular & Cellular Biology Lab (BIO 211): Instructor: Elmar Schmid, Ph.D.
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Table 1: Human traits & Mendelian inheritance in humans
Human trait
Dominant
Trait
Cleft in chin or cheeks
Dimples
- skin depressions
(D allele)
Free hanging ear lobe
Ear lobe
- hand freely
(E allele)
Widow’s peak
(skip if baldness exists)
Tasting of PTC
Interlocking fingers
Hair line has distinct point
in the center of the fore
head
(W allele)
Able to sense the bitter taste
of the molecule
phenylthiocarbamide (PTC)
on the tongue
(T allele)
Place left thumb on top of
the right thumb when
interlocking fingers
(F allele)
Able to roll tongue upwards
Recessive
Trait
No cleft, smooth chin and
cheeks
(2 d alleles)
Attached ear lobe
- earlobes are connected to the
head near the jaw bone
(2 e alleles)
Straight hair line
(2 w alleles)
Cannot taste this chemical
(2 t alleles)
Place right thumb over the
left
(2 f alleles)
No rolling possible
Tongue rolling
Bent little finger
Long palmar muscle
Pigmented iris
Finger hair
(R allele)
Little finger is bendable
towards the fourth finger
(“crooked little finger”)
(B allele)
Inside of wrist reveals three
tendons upon tightly
clenching your fist indicating
a long palmar muscle
(L allele)
Iris of the eyes shows
depositing of the brown
pigment melanin with
different density; brown,
hazel, violet, green eye color
(P allele)
All or some fingers have tiny
hair below the finger tip and
above the knuckle
(2 r alleles)
Little finger doesn’t bend
under force
(2 b alleles)
Fist clenching only reveals
two tendons on the wrist
inside
(2 l alleles)
Iris of eyes does not show
melanin pigmentation;
Blue eyes
(2 p alleles)
No hair visible on the middle
joint of the fingers; smooth
hair-less mid digits
(even after use of an magnifying
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SOUTHWESTERN COLLEGE
School of Mathematics, Science & Engineering
Intro Molecular & Cellular Biology Lab (BIO 211): Instructor: Elmar Schmid, Ph.D.
glass!)
Number of fingers
Index finger length
(a sex/genderinfluenced trait)
(M= male; f = female)
(M allele)
People are born with six
fingers (polydactyly)
(S allele)
People with shorter second
finger in comparison to
fourth finger
(MS or FS allele)
(2 m alleles)
People with fix fingers
(2 s alleles)
Second finger is longer than
the fourth finger
(Ms or Fs allele)

While the heritable human traits listed in the Table 1 above do not interfere with a
persons life and do not seems to confer any obvious advantages or disadvantages to
an individual possessing these traits, there is – unfortunately – many dominantrecessive inherited traits been described for our species which are associated with
human disorders leading to impairment of good health and a lot of human suffer

Many inherited disorders in humans are controlled by a single gene
- more than 1000 dominant or recessive traits are known
- these traits show therefore simple inheritance patterns, which can be described and
predicted by Mendel’s principles
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