3.19

3.19 describe patterns of monohybrid inheritance using a genetic diagram

Monohybrid: one gene (2 alleles)

P₁ x P₁ Monohybrid cross

Parental phenotypes: red and white (P₁)

Parental genotypes:  GG x gg

Meiosis à production of gametes G G g g 

Random fertilisation: 

F₁ cross F₁ x F₁

Phenotype: Red x Red (F₂)

Genotype: Rr x Rr

Meiosis à Gametes: R r R r

Fertilisation:

Monohybrid F₂ ratio     3:1

Genotypes of the F₂: 1RR: 2Rr: 1rr

Phenotype of the F₂: 3Red: 1White

(PREDICTION STATED BY RATIO: F₂ ratio of 3:1)