Punnett Squares

TraitsP - Parental Generation• Genotype: TT or tt• Gametes: T or tF1 – First Filial Generation• Genotype: Tt• Gametes: T or tF2 – Second Filial Generation• ** too complicated need to set up a Punnett

Square

Predicting traits

• The Punnett Square is a valuable tool for visualizing the probability of the inheritance of certain traits

Predicting traits

• Genotypes:• Genotypic ratio:• Phenotypes:

Phenotypic ratio: • % tall? • % short? %

Predicting traits

• Genotypes: TT, Tt, tt• Genotypic ratio:• Phenotypes:

Phenotypic ratio:• % tall? • % short?

Predicting traits

• Genotypes: TT, Tt, tt• Genotypic ratio: 1:2:1• Phenotypes:

Phenotypic ratio: • % tall? • % short?

Predicting traits

• Genotypes: TT, Tt, tt• Genotypic ratio: 1:2:1• Phenotypes: tall &

short• Phenotypic ratio: • % tall? • % short?

Predicting traits

• Genotypes: TT, Tt, tt• Genotypic ratio: 1:2:1• Phenotypes: tall &

short• Phenotypic ratio: 3:1• % tall? • % short?

Predicting traits

• Genotypes: TT, Tt, tt• Genotypic ratio: 1:2:1• Phenotypes: tall &

short• Phenotypic ratio: 3:1• % tall? 75%• % short?

Predicting traits

• Genotypes: TT, Tt, tt• Genotypic ratio: 1:2:1• Phenotypes: tall &

short• Phenotypic ratio: 3:1• % tall? 75%• % short? 25%

Problem 1

• #1 Two parents(P), one heterozygous red petal is crossed with a white petal flower. Red is dominant to white. What is the phenotypic ratio of the F1 generation?

Problem 1

• #1 Two parents(P), one heterozygous red petal is crossed with a white petal flower. Red is dominant to white. What is the phenotypic ratio of the F1 generation?

Rr Rr

RR rr

Problem 1

• Genotypic ratio:• Phenotypic ratio:• % of red petals:

Rr Rr

RR rr

Problem 1

• Genotypic ratio: 2:2• Phenotypic ratio:• % of red petals:

Rr Rr

RR rr

Problem 1

• Genotypic ratio: 2:2• Phenotypic ratio: 2:2• % of red petals:

Rr Rr

RR rr

Problem 1

• Genotypic ratio: 2:2• Phenotypic ratio: 2:2• % of red petals: 50%

Rr Rr

RR rr

Problem 2

• #2 Cross a homozygous tall with a heterozygous tall.

Problem 2

• #2 Cross a homozygous tall with a heterozygous tall. TT TT

Tt Tt

Problem 2

• Genotypic ratio:• Phenotypic ratio: • % of being tall: TT TT

Tt Tt

Problem 2

• Genotypic ratio: 2:2• Phenotypic ratio: • % of being tall: TT TT

Tt Tt

Problem 2

• Genotypic ratio: 2:2• Phenotypic ratio: 4• % of being tall: TT TT

Tt Tt

Problem 2

• Genotypic ratio: 2:2• Phenotypic ratio: 4• % of being tall: 100% TT TT

Tt Tt