Phenotype/Genotype Inheritance in Humans Classroom Activity
Name:
Karin Deutsch
Human have several single-gene traits that are easy to observe and which are controlled by genes that have only
two alleles. Based on the specific combination of alleles (AA, Aa = dominant phenotype; aa = recessive
phenotype) the trait is either present or absent. There is no “in between”. Many other human traits, such as eye
color and height are due to several pairs of genes, and the phenotypes show a continuous range of variation.
For the traits described in the following list, determine your phenotype and possible genotype.
Trait
l. Facial dimples: Best seen when smiling. With dominant
phenotype, you may have a dimple only on one side, or on
,"_both.
_
_
_
_
2. Bent little finger: A dominant allele causes the last joint
of the little fmger to dramatically bend inward toward the 4"‘
fmger. Lay both hands flat on a table relax your muscles, and
note whether your have a bent or straight little fmger.
3. Eye Color: Eye color, as well as hair and skin color, is a
complex trait. The main pigment is melanin, and the more
melanin, the darker the color. While the genetics of eye color
- is complex, alleles for the production of melanin dominate
those for lack of melanin. Evaluate your eyes as either brown
{M} or non-brown {ml-.
_
4. Free ear lobe: Dominant trait is for lobes to hang free.
With recessive phenotype, the lobes are attached directly to
the head.
5. lflid-digital hair: Some people have hair on the middle
segment of one or more of their fmgers, while others don’t.
Any hair at all is the dominant phenotype. Complete absence
_ ofhair is recessive.
' 6. Hand clasping: When the hands are clasped (without
thinking about itl), most people place their left thumb on top
of their right.
__
7. Early Onset Myopia (childhood):-Nearsightedness is a
complex trait with at least 4 gene loci involved, however the
heritability of myopia is very high and shows a dominant
_pattern.
8. Achondroplasia: The most frequent or of short-limb
dwarfism. Affected individuals (Aa) exhibit short stature
cause by shortening of the limbs. (AA individuals die before
birth}.
l 9. Chin cleft: A prominent cleft in the chin is inherited as the
dominant phenotype. The cleft is due to the bond structure
I which underlies the Y-shaped fissure of the chin. Females
_ appear to be less conspicuously affected than males.
10. Achoo syndrome: Autosomal dominant trait also called
photo sneeze reflex, usually 2 - 3 successive sneezes, when a
dark-adaptedperson suddenly is exposed to bright light.
Hair VVhorling_
PTC tasting
Symbol
I Dominant
_ Phenotype
dimples
'
D, d
Your
_PhGI10lH‘l6
d (no
dimples) _
_.
B, b
Your
genotype
bent
b
dd
'
bb
_
E, e
_
_
brown
E
_
I
_
I
F. f
free
H, h
_
' hair
Ee
(I know cause my dad has
brown eyes but nobody else
but not my mum or brothers)
but theoretically EE would be
a correct answer too
ff
f
_
h
hh
L
LL, Ll
m
mm
a
aa
,
L,l
left on top
M, m
myopic
_
A, a
C,c
_
' A, a
_
W, w
P, p
achondropla
| sia
cleft
sneezing
clockwise whorl
Taste
'c
A
W
P
cc
AA, Aa
_ WW,
Ww
PP, Pp
This assigmnent is from the Virtual Cell Biolo_:_-1 ft-' Classroom (http:/Xwww.scienceprofonline.com/virtual-cell-main.html ) on the free
science education website Science Prof Online (ScienceProfOnline.com). Visit the website to find more science education resources
such as lecture PowerPoints, practice test questions, review questions, science photos, videos and assigmnents.
Widow’s Peak
_
Tendons in Wrist
_ Ann folding
Toe Length {Second Bigger or Big Toe Bigger}
—
w
ww
T, t
present
T
TT, Tt
I missing
h
left top
second longer
present
A
T
f
w
s
hh
AA, Aa
T, t
F, f
W, w
Eyelid Fold
__
Peak
H, h
A, a
_ Hitchl‘n'ker’s Thumb
Web Fingers
Six Fingers
Fing_e_r Length
_ Handedness
W, w
T
_
,
Traits
—
S, s
F, f
H,h
i
present
6 fingers
short
— ll-uminant l
right
—
TT, Tt
ff
ww
ss
f (normal length) ff
HH, Hh ( I am
H
bothhanded but
since i have to
decide for
one...)
_
Recessive
Baldness [in males)
Presence
Body hair
Abundant
Little
“T
Absence
l
T
L
Bent pinkie
Able to bend
Not able to bend
Blood pressure rate
High
Low
Cleft in chin
Absence
Presence
‘ll
Crossing of thumbs
Left thumb over right thumb —
u in
_
_
Right thumb over left thumb
I_
Dimples
I
Earlobes
—
_
_
_
__
_
flittaizhed earlobes
Long eyelash
Short eyelash
Freckles
Presence
Absence
Hairline
widow's pealr
Straight
White hair streak
Normal hair color
Hair color
_
Right handedness
Absence
Pres enoe
Bro ad lips
Thin lips
Presence
Absence
Mongolian eye fold
Presence
Abs en ce
Nose shape
Roman nose (bump)
Straight
Nose width
Broad nose
Narrow nose
Lips width
I
F
—
Left handedness
Handedness
Hiti:hhiker's thumbs
Mid-digital hair
C
_
Absen oe
Definite free earlobes
Eyelash length
J
__
Presence
1'
Number of fingers
Six fingers
—l=iu'e fingers
Rh factor in blood
_ -1-
Rh factor positive l._+)
Rh factor negative [-1
Toe length
Second toe longer than first toe
First toe longer than second toe
Tone hearing
Tone deafness
Normal hearing
Tongue rolling [side -edges up]
Ability to roll tongue
Inability to roll tongue
Vision
Astigmatism
Normal vision
Webbed fingers
Presence
Absence
This assignment is from the Virtual Cell Biology Classroom (htlpzf/www.scienceprofonline.comfvirtual-cell—main.html ) on the free
science education website Science Prof Online (ScienceProfOnline.com). Visit the website to find more science education resources
such as lecture PowerPoints, practice test questions, review questions, science photos, videos and assigmnents.
n
LIST OF
5‘
.
HUMAN
S
u
—
DOIYEWIANT
REGESSIVE
Right handedness
Roll tongue
Roman
Absence of smell
PIYE-fl‘lfl;lll1'E gray hair
Astigmatism
Piebald suntan
Free eru'lohe.s
Rolled ear time
Taste PTC
Left hantiedness
Not roll tongue
Normal. nose
Presence? of smell
1"-To prlcnlatute gray hair:
Normal vision
Noi'1na.l skin color
Attached earl lobes
Ear rims not rolled
Not taste PTC.‘
E€u'|.y baldness in males
Nolmfll
Brown eye color
l-lazel or green eye color
Darlr hair color
Blue or grtty eye color
Blue or gray eye color
Light hair color
ID-arl-t sltin. GDIDI
Light Skin color
Wavy or curly hair
Polytlacliyl {E fingers and toes}
Straight hair [in Asians}
Blood types A, E. AB
Blood type Rh positive
Near sighted vision
Green eyelcolor
Straight .l1aiir
Norrrtal fingers
Curly hair
Blood type 0
Blood
Rh negative
vision
Blue eye color
Gray eye color
Blue eye color
Green eye color
Wid%ow’s peat;
Hair on mitl-tligital knuckle
Gray eye color
No Witiow’s
No hair on tttidedigital
Dimplcs
1"-lo dimples
Second toe longer than big toe
“lrIli.‘l.-cit-l-lii~:cr"* ‘thumb
A
Short fingers
Non-l-red hair
Nomial coior vi?:si.on
Second. toe shorter than big to-e
i*iDl'I!1i1i thumb
Normal length fingers
Red hair
Red--green color hlind. [Sex li.nl:.ei:‘i)
Abundant. hotly hair
Little body hail‘
White forelock
“Mongolian “ fold” eyes
F-ersightedness
Broiacl lips
Large eyes
eyelashes
nostrils
No white foneloclt
No fold
NEll'l11-ill vision
Thin lips
Small. eyes
Short tcyelashes
liarrow nostrils
Short stature {many genes}
Tull stature
Webbed. fingers
I-Iigh blood pressure
Normal
Noimal fingers
Normal blood pressure
Hemophilia
Norrnzal
Di.abotcs- mcl.litu5
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