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.**

**Cross two homozygous red flowers.**

**_______________ X _______________**

** **

genotypic ratio: ___________________________

phenotypic ratio: __________________________

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

**_______________ X _______________**

** **

genotypic ratio: ___________________________

phenotypic ratio: __________________________

**Cross two heterozygous flowers.**

**_______________ X _______________**

** **

genotypic ratio: ___________________________

phenotypic ratio: __________________________

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

**_______________ X _______________**

** **

genotypic ratio: ___________________________

phenotypic ratio: __________________________

**Cross a heterozygous flower with a white flower.**

**_______________ X _______________**

** **

genotypic ratio: ___________________________

phenotypic ratio: __________________________

**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.**

** **

**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 _________________

**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 _________________

**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 _________________

**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 _________________

**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 _________________

- Why does this problem have not clear cut answer?

- What could you do to determine the parent genotypes?

- What is this process called?