AP BIOLOGY

HEREDITY

INCOMPLETE DOMINANCE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
In incomplete dominance, the heterozygote offspring shows ____
A
a phenotype of the dominant parent
B
a phenotype of the recessive parent
C
a phenotype that is an intermediate or a blend of the 2 homozygous phenotypes
D
a phenotype that shows both alleles expressed at the same time
Explanation: 

Detailed explanation-1: -Answer and Explanation: A situation in which the heterozygote offspring of two homozygotes show a phenotype intermediate between those of the parents is called incomplete dominance. Incomplete dominance occurs when the dominant allele does not completely dominate the recessive allele.

Detailed explanation-2: -Incomplete dominance occurs in the heterozygote, in which the dominant allele does not dominate the recessive allele entirely; rather, an intermediate trait appears in the offspring. Codominance occurs when the alleles do not show any dominant and recessive allele relationship.

Detailed explanation-3: -However, sometimes the heterozygote displays a phenotype that is an intermediate between the phenotypes of both homozygote parents (one of which is homozygous dominant, and the other of which is homozygous recessive). This intermediate phenotype is a demonstration of partial or incomplete dominance.

Detailed explanation-4: -Mendel’s results were groundbreaking partly because they contradicted the (then-popular) idea that parents’ traits were permanently blended in their offspring. In some cases, however, the phenotype of a heterozygous organism can actually be a blend between the phenotypes of its homozygous parents.

Detailed explanation-5: -Incomplete dominance occurs when neither trait is truly dominant over the other. This means that both traits can be expressed in the same regions, resulting a blending of two phenotypes. If a white and black dog produce a gray offspring, this is an example of incomplete dominance.

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