Incomplete Dominance Question Grade 11 Need an biology expert

In summary, incomplete dominance is a genetic phenomenon where neither of the two alleles is completely dominant over the other, resulting in a heterozygous individual expressing a phenotype that is a blend of both alleles. It differs from complete dominance where one allele is completely dominant, resulting in the dominant allele being expressed in the phenotype. Incomplete dominance can occur in both plants and animals, and is inherited through the same genetic mechanisms as other Mendelian traits. Real-life examples include flower color in snapdragons and coat color in dog breeds such as the Labrador Retriever.
  • #1
Madara Uchiha
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Homework Statement



Hey guys...

The palomino horse results from the combination of two incompletely dominant genes, one codes for the colour chestnut and the other for cream. Determine the expected genotypic and phenotypic ratios for the following crosses:

a.)chestnut and cream
b.)palomino and cream
c.) palomino and palominoPlease this is the only question I didn't understand for my homework.. However I got 100% for phenotype for all options... Please correct me if I'm wrong and tell me what I'm doing right and wrong but mostly wrong :)

Homework Equations



What :S :?

The Attempt at a Solution

Let PP represent the allele for palomino.
Let PC1 represent the allele for cream.
Let PC2 represent the allele for chestnut.a.)

_____PC1______PC1
PC2__PC1PC2___PC1PC2
PC2__PC1PC2___PC1PC2Genotype: 50% Cream; 50% Chestnut
Phenotype: 100% PC1PC2b.)____PC1____PC1
PP__PPPC1__PPPC1
PP__PPPC1__PPPC1Genotype: 50% Cream; Palomino 50%
Phenotype: 100% PPPC1

c.)____PP____PP
PP__PPPP__PPPP
PP__PPPP__PPPPGenotype: 100% Palomino
Phenotype: 100% PPPP
 
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  • #2
A few points:

1) When the question asks about about genotype ratios, it's talking about the different combinations of alleles. For example, 50% PC1PC2, 50% PC1PC1 is a genotype ratio. A phenotype ratio would describe the numbers of horses of each color, for example, 50% palomino, 50% cream.

2) Pp is not the allele for palomino. In fact, phenotypes are not represented by a single allele. Rather, phenotypes are associated with pairs of alleles (e.g. PC1PC1 gives the cream phenotype, whereas Pc2Pc2 gives the chesnut phenotype). Read the question again, focusing on the first two sentences. What is the genotype associated with the palomino phenotype? If you still don't understand, you may need to re-read the section in your textbook on incomplete dominance.
 

1. What is incomplete dominance?

Incomplete dominance is a genetic phenomenon where neither of the two alleles is completely dominant over the other. This results in a heterozygous individual expressing a phenotype that is a blend of both alleles.

2. How is incomplete dominance different from complete dominance?

In complete dominance, one allele is completely dominant over the other, resulting in the dominant allele being expressed in the phenotype. In incomplete dominance, neither allele is completely dominant, resulting in a mixture of both alleles being expressed in the phenotype.

3. Can incomplete dominance occur in both plants and animals?

Yes, incomplete dominance can occur in both plants and animals. It is a common genetic phenomenon observed in a variety of species.

4. How is incomplete dominance inherited?

Incomplete dominance is inherited through the same genetic mechanisms as other Mendelian traits. The alleles for incomplete dominance follow the principles of segregation and independent assortment.

5. Are there any real-life examples of incomplete dominance?

Yes, there are several real-life examples of incomplete dominance. One well-known example is the flower color in snapdragons, where the heterozygous genotype results in a mixture of red and white petals. Another example is the coat color in some dog breeds, such as the Labrador Retriever, where the heterozygous genotype results in a blend of black and yellow fur.

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