Name: __________________________________  Date:__________________________

 

Practice with Punnett Squares II

 

Trait: Flower Color

Alleles: Red and white

Dominant: Red

Recessive: White

 

Directions: Write an equation (in symbols) for each of the following crosses. Set up a Punnett square. Identify the genotypic and phenotypic ratios for the possible offspring.

 

  1. Cross two homozygous red flowers.

  


 

_______________  X _______________

 

genotypic ratio: ___________________________

 

 

phenotypic ratio: __________________________

 

 

 

  1. Cross a homozygous red flowers with a heterozygous flower.

_______________  X _______________

 

genotypic ratio: ___________________________

 

 

phenotypic ratio: __________________________

 

 

 

  1. Cross two heterozygous flowers.

  


 

_______________  X _______________

 

genotypic ratio: ___________________________

 

 

phenotypic ratio: __________________________

 

 

 

  1. Cross a homozygous red flower with a white flower.

  


 

_______________  X _______________

 

genotypic ratio: ___________________________

 

 

phenotypic ratio: __________________________

 

 

  1. Cross a heterozygous flower with a white flower.

  


 

_______________  X _______________

 

genotypic ratio: ___________________________

 

 

phenotypic ratio: __________________________

 

 

  1. Cross two white flowers.

  


 

_______________  X _______________

 

genotypic ratio: ___________________________

 

 

phenotypic ratio: __________________________

 

 

 

 

 

 

 

Directions: Look at the results of the following crosses. Based on the phenotypes of the parent plants and the phenotypic ratios of the offspring, try to determine the genotypes of the parent plants. To determine the phenotypic ratios of the offspring, reduce the ratios and compare the results to the ratios above that you are more familiar with. Example: 746 red: 230 white reduces to 3.2 red: 1 white which is very close to a 3 red: 1 white ratio.

 

  1. Red X Red produced 746 red and 230 white offspring.

 

Phenotypic ratio of the offspring is: __________ญญญญญญญญญญ_____________________________

 

Look at problems 1-6 above. Which problem has results most like this problem? _______

 

The parent genotypes are most likely: ________________ X _________________

  1. Red X White produced 350 red and 0 white offspring.

 

Phenotypic ratio of the offspring is: __________ญญญญญญญญญญ_____________________________

 

Look at problems 1-6 above. Which problem has results most like this problem? _______

 

The parent genotypes are most likely: ________________ X _________________

 

 

  1. White X White produced 0 red and 478 white offspring.

 

Phenotypic ratio of the offspring is: __________ญญญญญญญญญญ_____________________________

 

Look at problems 1-6 above. Which problem has results most like this problem? _______

 

The parent genotypes are most likely: ________________ X _________________

 

 

  1. Red X White produced 248 red and 241 white offspring.

 

Phenotypic ratio of the offspring is: __________ญญญญญญญญญญ_____________________________

 

Look at problems 1-6 above. Which problem has results most like this problem? _______

 

The parent genotypes are most likely: ________________ X _________________

 

 

  1. Red X Red produced 523 red and 0 white offspring.

 

Phenotypic ratio of the offspring is: __________ญญญญญญญญญญ_____________________________

 

Look at problems 1-6 above. Which problems have results most like this problem? _______ or _________

 

The parent genotypes are most likely: ________________ X _________________ or

 

________________ X _________________

 

  1. Why does this problem have not clear cut answer?

 

 

  1. What could you do to determine the parent genotypes?

 

 

 

  1. What is this process called?