Name: Natalie
Status: Educator
Grade: 9-12
Location: IN
Country: United States
Date: February 2007
Question:
What is the easiest way to teach students the
difference between codominance and incomplete dominance? They
always confuse them.
Replies:
Codominance - A form of inheritance in which both alleles
are equally shown.
Blood typing is a great example.
AB blood is the codominant relationship between the A protein and B
protein both expressing themselves completely.
AO (type O allele means there is no protein), A is dominant and you
see type A phenotype.
BO is the same except you see the B phenotype. Type O is recessive.
Incomplete dominance - A form of inheritance in which the
heterozygous alleles are both expressed,
resulting in a combined phenotype.
The one example that most books
give is seen in some flower colors.
A red and a white allele gives pink. If it were codominance, you
would see the red and white colors.
Incomplete dominance is most commonly found in plants.
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.
