Beth Howard Genetics

Definition of Co-Dominance:

In Non-Mendelian Genetics, Co-Dominance results in.....

• both phenotypes (traits) of the parents being present in the offspring.

• a mixture of the parent phenotypes (traits) shown in the offspring.

• the dominate trait showing up in the offspring.

• the recessive trait showing up in the offspring.

Co-Dominance Question 1:

In shorthorn cattle, when a red bull (RR) is crossed with a white cow (WW), all the offspring are roan (RW).

What would be the phenotype characteristics of the roan bull?

• The roan offspring will show both parent characteristics, so it will be both red and white in color.

• The roan offspring will be all red.

• The roan offspring will be all white.

• The roan offspring will be pink, a mixture of red and white.

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Co-Dominance Question #2

In shorthorn cattle, when a red bull (RR) is crossed with a white cow (WW), all the offspring are roan (RW).

On a clean sheet of paper, create a Punnett Square with the crossing the following information.

Cross a roan bull and a roan cow.

What phenotypic and genotypic ratios would you get?

• Genotypic Ratio- 1 RR: 2 RW: 1 WW

  Phenotypic Ratio- 1 Red: 2 Roan: 1 White

• Genotypic Ratio- 3 RR: 1 RW: 1 WW

  Phenotypic Ratio- 1 Red: 3 Roan: 0 White

• Genotypic Ratio- 1 RR: 3 RW: 0 WW

  Phenotypic Ratio- 1 Red: 3 Roan: 0 White

• Genotypic Ratio- 1 RR: 2 RW: 0 WW

  Phenotypic Ratio- 3 Red: 1 Roan: 0 White

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Co-Dominance Question #3:

In shorthorn cattle, when a red bull (RR) is crossed with a white cow (WW), all the offspring are roan (RW).

On a clean sheet of paper, construct the Punnett Square for the following P-Generation.

What phenotypes would you expect from a cross between a red bull and a white cow?

• The phenotypes of the offspring will be 100% roan.

• The phenotypes of the offspring will all 25% white and 75% roan.

• The phenotypes of the offspring will be 75% roan and 25% white.

• The phenotypes of the offspring will be 25% white, 25% red, and 50% roan.

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Co-Dominance Question #4

In some chickens, the gene for feather color is controlled by co-dominance. The genotype for black is BB and the genotype for white is WW. The heterozygous phenotype is known as erminette (BW).

What would be the phenotype characteristics of the erminette chicken?

• The phenotype characteristics of an erminette chicken will be that it has both black and white feathers.

• The phenotype characteristics of an erminette chicken will be that it has only black feathers.

• The phenotype characteristics of an erminette chicken will be that it has only white feathers.

• The phenotype characteristics of an erminette chicken will be that is will be gray, a mixture of both parent traits.

Tags

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Co-Dominance Question #4 (a-c)

In some chickens, the gene for feather color is controlled by codominance. The genotype for black is BB and the genotype for white is WW. The heterozygous phenotype is known as erminette (BW).

a. What is the genotype for chickens with black feathers?

b. What is the genotype for chickens with white feathers?

c. What is the genotype for erminette chickens?

• Chickens With Black Feathers: BB

  Chickens With White Feathers: WW

  Erminette Chickens: BW

• Chickens With Black Feathers: BB

  Chickens With White Feathers: Bb

  Erminette Chickens: bb

• Chickens With Black Feathers: bb

  Chickens With White Feathers: WW

  Erminette Chickens: Bb

• Chickens With Black Feathers: BB

  Chickens With White Feathers: WW

  Erminette Chickens: RW

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Co-Dominance Question #5 (a-c)

In some chickens, the gene for feather color is controlled by codominance. The genotype for black is BB and the genotype for white is WW. The heterozygous phenotype is known as erminette (BW).

On a clean sheet of paper, create a Punnett Square crossing the following genotypes.

If two erminette chickens were crossed, what is the probability that:

a. They would have a chicken with black feathers?

b. They would have a chicken with white feathers?

c. They would have a chicken with black and white feathers.

• Chicken with Black Feathers- 25%

  Chicken with White Feathers- 25%

  Erminette Chicken- 50%

• Chicken with Black Feathers- 25%

  Chicken with White Feathers- 25%

  Erminette Chicken- 25%

• Chicken with Black Feathers- 25%

  Chicken with White Feathers- 50%

  Erminette Chicken- 25%

• Chicken with Black Feathers- 25%

  Chicken with White Feathers- 75%

  Erminette Chicken- 50%

Tags

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Co-Dominance Question #6 (a-c)

In some chickens, the gene for feather color is controlled by codominance. The genotype for black is BB and the genotype for white is WW. The heterozygous phenotype is known as erminette (BW).

On a clean sheet of paper, create a Punnett Square crossing the following genotypes.

If a chicken with black feathers and a chicken with white feathers are crossed. What is the probability that will have:

a. An erminette chick?

b. A chicken with black feathers?

c. A chicken with white feathers?

• Erminette Chicken- 100%

  Chicken with Black Feathers- 0%

  Chicken with White Feathers- 0%

• Erminette Chicken- 25%

  Chicken with Black Feathers- 25%

  Chicken with White Feathers- 50%

• Erminette Chicken- 50%

  Chicken with Black Feathers- 25%

  Chicken with White Feathers- 25%

• Erminette Chicken- 25%

  Chicken with Black Feathers- 50%

  Chicken with White Feathers- 50%

Tags

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Co-Dominance Question #7

In humans, straight hair (SS) and curly hair (CC) are co-dominant traits that result in hybrids that have wavy hair (SC).

On a clean sheet of paper, create a Punnett Sqare that crosses the P-Generation listed below.

Cross a curly hair female with a wavy haired male.

a. What are the chances of having a curly haired child?

b. What are the chances of having a straight haired child?

c. What are the chances of having a wavy haired child?

• Wavy Hair- 50%

  Straight Hair- 0%

  Curley Hair- 50%

• Wavy Hair- 100%

  Straight Hair- 0%

  Curley Hair- 0%

• Wavy Hair- 25%

  Straight Hair- 25%

  Curley Hair- 50%

• Wavy Hair- 50%

  Straight Hair- 50%

  Curley Hair- 50%

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