3.21

3.21 predict probabilities of outcomes from monohybrid crosses

Chances of outcomes of offspring from monohybrid involving just the one gene

Parents (phenotype): Red x White (monohybrids)

Genotype: RR x rr

Meiosis R, R, r, r (homozygous) à Random fertilisation

Genotype offspring: Rr (all) 100%

(F₁) Phenotype offspring: ALL red

F₁ cross F₁ x F₁

Parent Phenotype: Red x Red

Parent Genotype: R, r, R, r (heterozygous)

Meiosis à Random fertilisation

Genotype offspring: RR: 2Rr: rr

Phenotype ratio (F₂): 3:1 (red:white)