Incomplete Dominance

1
Incomplete Dominance Codominance
2
Incomplete Dominance
red
white
pink

• Defined When neither allele is dominant and the
  alleles blend together
• No recessive allele
• More then 2 different phenotypes can occur
• Ex Many flower colors

3
Example Cross a homozygous red 4 oclock flower
(RR) with a homozygous white flower (WW).

• List the genotypes.
• 4RW
• List the phenotypes.
• 4 Pink

W W
R
R
W
W
R R
pink
pink
R
R
W
W
pink
pink
4
Example Cross one heterozygous pink (RW) 4
oclock flower with a White flower (WW).

• List the genotypes.
• 2RW, 2WW
• List the phenotypes.
• 2 Pink, 2White

R W
R
W
W
W
W W
white
pink
R
W
W
W
pink
white
5
Codominance

• Defined When both alleles are dominant and
  equally expressed
• The colors do NOT blend together, but are equally
  seen
• Ex Cattle Coat
• Red cow x White cow
• Roan Cow
• Ex Human Blood types
• Type A x Type B Type AB

red
white
roan
6
Multiple Alleles

• Defined More then 2 alleles control a trait
• Ex Blood Type has 3 alleles
• Dominant A allele
• Dominant B allele
• Recessive O allele
• A and B allele are equally codominant

7
Ex Cross Jason who is homozygous for type A
blood with Maria who is homozygous for type B
blood.

• List the genotypes.
• 4AB
• List the phenotypes.
• 4 type AB blood

B B
A A
A
B
A
B
A
B
A
B
8
Ex Cross Mike who is heterozygous for type A
blood with Lisa who is heterozygous for type B
blood.

• List the genotypes.
• 1AB, 1Ao, 1Bo, 1oo
• List the phenotypes.
• 1 type AB blood
• 1 type A blood
• 1 type B blood
• 1 type o blood
• Probability of Heterozygous individual?
• 75

B o
A o
A
A
B
o
B
o
o
o