1. The gene for blood type has 3 possible alleles.
Multiple Alleles
In traits with multiple alleles, each individual can carry any two of the several possible alleles.
Ex. BLOOD TYPE
The gene for blood type has 3 possible alleles.
IA, IB, and i

2. Blood Type In this case both IA and IB are dominant to i (recessive).
IA and IB are codominant (both expressed)
So... there are four human blood types
Genotype
Phenotype
IAIA, IAi
Blood type A
IBIB, IBi
Blood type B
IAIB
Blood type AB ii
Blood Type O

3. Multiple Alleles Alleles for blood type are: -IA (dominant)
-IB (dominant)
-i (recessive)

4. Blood Type Practice Problems:
1. A mother is AB and a father is O. Draw the punnett square.
IA IB i
What is the probability their offspring will have A type blood? ____
Can they have an offspring with O blood? ____

5. Blood Type
2. A mother is IAi and a father is IB IB. Draw the punnett square.
What is the probability their offspring will have B type blood?
Can they have an offspring with O blood?

6. Blood Type
3. If a child has AB blood which of the following could NOT be the parents?
a) ii, IAIB
b) IAi, IBIB
c) IBIB, IAIA
d) IAi, IBi