In a testcross,an organism with a dominant phenotype,but unknown genotype is crossed with which of the following to establish its genotype?
A)homozygous dominant
B)heterozygous
C)homozygous recessive
D)heterozygous dominant
E)monohybrid dominant

Question

Quizplus · Accepted Answer

In a testcross, the best choice to establish the genotype of an organism with a dominant phenotype, but unknown genotype, is to cross it with a homozygous recessive individual. This is because the offspring resulting from this cross will all show the dominant phenotype if the unknown organism is homozygous dominant or heterozygous, but only half of them will show the dominant phenotype if the unknown organism is heterozygous. By analyzing the phenotypic ratios of the offspring, we can determine the genotype of the unknown organism.

In a Testcross,an Organism with a Dominant Phenotype,but Unknown Genotype