The genotype of an organism that expresses a dominant trait can be determined by
A) crossing the organism with a homozygous dominant organism.
B) crossing the organism with a heterozygous dominant organism.
C) crossing the organism with a homozygous recessive organism.
D) observing the phenotype of the progeny from any cross.
E) observing the genotype of the progeny from any cross.

Question

Quizplus · Accepted Answer

Crossing with a homozygous recessive organism (test cross) reveals the genotype of the dominant phenotype by observing the offspring. If any offspring show the recessive trait, the organism is heterozygous.

The Genotype of an Organism That Expresses a Dominant Trait