CODOMINANCE GRADE 9

3. EXAMPLE OF CODOMINANCE
For example, RB fish will have scales that are both red and
blue.

4. -this result when one allele is not
dominant over the other.
CODOMINANCE
-this resulting heterozygotes exhibit
the traits of both parents.
-
when an organism has two different alleles
(i.e., is a heterozygote), it’ll express both at
the same time.

5. ACTIVITY 3.1 Ra-tio-Me
Answer the following questions. Provide a
Punnett square to support your answers where
indicated. Express probabilities as percentages.
1. In some chickens, the gene for feather color
is controlled by codominance. The allele for
black is B and the allele for white is W. The
heterozygous phenotype is known as speckled/
erminette.
A. What is the genotype for black chickens?
B, What is the genotype for white chickens?
C. What is the genotype for speckled/erminette chickens?
2. If two speckled/erminette chickens were crossed, what is the probability that: (use
a Punnett square)
A. They would have a black chick?
B. They would have a white chick?

6. ACTIVITY 3.1 Ra-tio-Me
3. A black chicken and a white chicken are crossed. What is
the probability that they will have speckled/erminette chicks?

7. Make a cross between a homozygous black cow and a black
and white cow. Use the Punnett square to solve the problem
and answer the guide questions.

8. GUIDE QUESTIONS:
1. What are the offspring in a cross between a
homozygous black cow and a black and white
cow?
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2. What are the possible genotypes?
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9. CODOMINANCE