Mendel found that pea plants expressing a recessive trait
A)were pure-breeding.
B)appeared only in the first generation of a cross between two pure-breeding plants expressing contrasting forms of a trait.
C)disappeared after the second generation.
D)could be produced only if one of the parents expressed the recessive trait.
E)were none of these.

Question

Quizplus · Accepted Answer

Mendel found that expression of a recessive trait in pea plants was only possible if both parents carried at least one copy of the recessive allele. Therefore, when a recessive pea plant was crossed with a homozygous dominant plant, all the offspring in the first generation would be heterozygous, masking the recessive trait. However, in the second generation, the recessive trait reappeared in a 3:1 ratio, indicating that the heterozygous offspring were carriers of the recessive allele. These recessive pea plants expressing the recessive trait were pure-breeding, meaning that they would consistently produce offspring expressing the same trait.

Mendel Found That Pea Plants Expressing a Recessive Trait