Download Incomplete dominance

Combining Genes Lab Reflection

Did your baby look more like you or your
partner? Why?
#52 Incomplete
Dominance
INCOMPLETE DOMINANCE!
• Incomplete dominance happens when two
alleles are neither dominant nor recessive
• Neither of the two alleles in a gene pair
masks or hides the other.
• The result is a complete blending of traits
Incomplete Dominance in
Humans
Skin color
 Hair texture
 Voice Pitch
 Height
 Hand Size
 Lip Protrusion
 Some Genetic Disorders: Sickle Cell
Anemia, Tay Sachs Disease

How do we represent the genotypes of
incomplete dominance traits?
 We use all CAPITAL LETTERS
EX: RY, RW, BW….etc
• If we cross breed a pure purple flowering
plant with a pure white flowering plant,
what would be the resulting offspring?

What is the genotype of a pure
purple flowering plant?  PP

What is the genotype of a pure white
 WW
flowering plant?

P
PP x WW
W
W
PW
PW

Genotype
0 % PP
0 % WW
100 % PW

P
PW
PW
Phenotype
0 % Purple
0 % White
100 % Lavender
How would you represent an incomplete
dominance cross between a pure red
flower and a pure yellow flower?

What is the genotype of a pure red
flowering plant?
 RR

What is the genotype of a pure
yellow flowering plant?  YY

R
RR x YY
Y
Y
RY
RY

Genotype
0 % RR
0 % YY
100 % RY

R
RY
RY
Phenotype
0 % Red
0 % Yellow
100 % Orange
PURE GOLD
Breeding a pure brown
with a pure white…

B
BB x WW
W
W
BW
BW

Genotype
0 % BB
0 % WW
100 % BW

B
BW
BW
Phenotype
0 % Brown
0 % White
100 % Palomino

What is the genotype of a hybrid
orange flowering plant?  RY

R
RY x RY
R
Y
RR
RY

Genotype
25 % RR
25 % YY
50 % RY

Y
RY
YY
Phenotype
25 % Red
25 % Yellow
50 % Orange