To identify whether an organism exhibiting a dominant trait is homozygous or heterozygous for a specific allele, a scientist can perform a test cross. The organism in question is crossed with an organism that is homozygous for the recessive trait

, and the offspring of the test cross are examined.

What is an example of a test cross?

Test cross is a cross between an organism with unknown genotype and a recessive parent. It is used to determine whether an individual is homozygous or heterozygous for a trait. Example: ... The white flower must be homozygous for the recessive allele, but the genotype of the violet flower is unknown.

What is a typical test cross?

In a typical test cross, an organism showing a dominant phenotype (and whose genotype is to be determined) is crossed with the recessive parent instead of self-crossing. The progenies of such a cross can easily be analysed to predict the genotype of the test organism.