Page 19 - Genetics_FULL

L 

C

What Are Codominant Alleles?

All the pea plant characteristics that Mendel studied had dominant and recessive alleles.
But sometimes traits are controlled by codominant alleles that are neither dominant nor
recessive. Both alleles are expressed in the offspring. Chicken feather color is an example
of codominance.

Expression of Codominant Alleles

W W
B
When homozygous black and homozygous white F F F F B
chickens are crossed, the offspring inherit one allele
for each color. Both alleles are expressed, resulting
in a black and white feather pattern.

B
F F W

F B F B

B
W
B
F W F F F F W
Codominant alleles are
symbolized using capital
letters with superscripts.

W
B
B
F W F F F F W

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