Mendel’s Genetic Experiments with Pea Plants

tall short

P1

(parental

generation)

F1

(first filial

generation)

F2

(second filial

generation)

X

tall tall tall short

cross pollination

self pollinate

produced a ratio of tall:short, 3:1(for hundreds of offspring)

all tall(hundreds)

Mendel’s Theory of GeneticsDominant and Recessive Alleles

• For the trait height in pea plants, T = tall and t = short.• If a plant has a T allele and a T allele (TT), would it be

tall or short?

tall• If a plant has a T allele and a t allele (Tt), would it be

tall or short?

tall• If a plant has a t allele and a t allele (tt), would it be tall

or short?

short

TT tt

T t T t

T T T t t t

tall short

P1

F1

F2

X

X

T t

all tall tall

tall tall tall short

purebred purebred

hybrid