Codominance Punnett Squares

Front

What is codominance?

Back

Codominance is a genetic scenario where both alleles in a heterozygote are fully expressed, resulting in offspring with a phenotype that is neither dominant nor recessive. Example: In flowers, red (RR) and blue (BB) parents produce speckled (RB) offspring.

Front

What is a Punnett Square?

Back

A Punnett Square is a diagram used to predict the genotypes of a particular cross or breeding experiment. It shows the possible combinations of alleles from the parents.

Front

What is the phenotypic ratio of a cross between a red flower (RR) and a speckled flower (RB)?

Back

The phenotypic ratio is 2 red (RR) to 2 speckled (RB).

Front

What are alleles?

Back

Alleles are different forms of a gene that can exist at a specific locus on a chromosome. They can be dominant or recessive.

Front

What is the difference between codominance and incomplete dominance?

Back

In codominance, both alleles are fully expressed in the phenotype (e.g., speckled flowers). In incomplete dominance, the phenotype is a blend of the two alleles (e.g., pink flowers from red and white parents).

Front

What is the inheritance pattern of a calico cat?

Back

Calico cats exhibit codominance, showing both orange and black fur due to the presence of both alleles.

Front

What does a genotype represent?

Back

A genotype is the genetic makeup of an organism, represented by the alleles it possesses (e.g., RR, RB, BB).

Front

What is the expected outcome of a cross between two heterozygous codominant flowers (RB x RB)?

Back

The expected outcome is 1 red (RR), 2 speckled (RB), and 1 blue (BB), resulting in a phenotypic ratio of 1:2:1.

Front

What is the significance of the dominant allele in a genetic cross?

Back

The dominant allele is the one that is expressed in the phenotype when present, overshadowing the effect of the recessive allele.

Front

How do you determine the phenotypic ratio from a Punnett Square?

Back

Count the number of times each phenotype appears in the Punnett Square and express it as a ratio.