Incomplete and Codominance

Front

What is codominance in genetics?

Back

Codominance is a form of inheritance where both alleles in a heterozygote are fully expressed, resulting in a phenotype that is neither dominant nor recessive. An example is a roan cow, which has both red and white fur.

Front

What is the phenotypic ratio expected from a cross between two roan cows?

Back

The expected phenotypic ratio is 1:2:1, which means 1 red, 2 roan, and 1 white.

Front

Define incomplete dominance in genetics.

Back

Incomplete dominance is a form of inheritance where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes. For example, in snapdragons, red (RR) and white (rr) flowers produce pink (Rr) flowers.

Front

What is the probability of two pink snapdragons producing pink offspring?

Back

The probability is 50%.

Front

What are the phenotypes produced when crossing a red flower (RR) with a speckled flower (RB)?

Back

The phenotypes produced are 2 red flowers and 2 speckled flowers.

Front

What is the phenotypic ratio when crossing two speckled flowers (RB)?

Back

The phenotypic ratio is 1 red, 2 speckled, and 1 blue.

Front

How does codominance differ from incomplete dominance?

Back

In codominance, both alleles are fully expressed in the phenotype, while in incomplete dominance, the phenotype is a blend of the two alleles.

Front

What is the expected percentage of gray offspring when crossing black and white cats exhibiting incomplete dominance?

Back

The expected percentage of gray offspring is 50%.

Front

What is a Punnett square and how is it used in genetics?

Back

A Punnett square is a diagram used to predict the genotypes of offspring from a genetic cross. It shows the possible combinations of alleles from the parents.

Front

What is the significance of the 1:2:1 ratio in genetic crosses?

Back

The 1:2:1 ratio indicates the expected distribution of phenotypes in the offspring when both parents are heterozygous for a trait.