Codominance
• What does co- mean?
• _____________ expresses both alleles’
conditions
– Ex.
• Usually uses both capital letters
– Key:
Codominant Punnett Square
Key:
__
__
__
___ ___
__
___
Genotype and
Phenotype Proportions
of offspring:
___
Now let’s cross two heterozygotes.
__
__
__
__
__
__
__
__
Results:
Polygenic Inheritance
• What does poly- mean?
• Trait controlled by _______________
– May be on ________________ chromosomes
• Shows a _______, ___________ is most
common phenotype
• __________________ case letters used
_____________: A polygenic trait
Number of Genes Involved in Skin Color
Expected distribution- 4
genes
Number of individuals
Observed
distribution of skin
color
Expected
distribution- 1 gene
Light
Range of skin color
Expected
distribution- 3
genes
Dark
Skin Color
• Due to __ genes
• Genotypes darkest to lightest:
Influence of External Environment
• Example(s):
• Notes:
Influence of Internal Environment
• Example(s):
• Notes:
Blood type quick facts
• ______________ are called erythrocytes
• Proteins on their surfaces are called
__________, controlled by _______
• _________ make ____________ to
__________________
– Examples of foreign substances:
• 4 phenotypes:
• 3 alleles:
Phenotype A
• Notes:
• Surface molecule
__ is produced.
Surface molecule A
Phenotype B
• Notes:
• Surface molecule ___
is produced.
Surface molecule B
Phenotype AB
Surface molecule B
• The lA and lB alleles are
____________.
• Notes:
Surface molecule A
Phenotype O
_____ antigens produced
Use your knowledge to fill out this chart
Blood Type
A
B
AB
O
Antigens
Antibodies
Can receive Can give to
from
Possible genotypes for each
phenotype:
•A=
•B=
• AB =
• O=