Question

What is the reason for doing a test cross?

a) To determine genotype
b) To determine phenotype
c) To create genetic diversity
d) To observe codominance

Answer 1

A test cross is done to determine if an organism expressing a dominant trait is a homozygote or a heterozygote. By crossing an organism with the dominant phenotype with a homozygous recessive organism, the resulting offspring can help determine the genotype of the dominant-expressing organism.

Step-by-step explanation:

The reason for doing a test cross is to determine whether an organism expressing a dominant trait is a homozygote or a heterozygote. In a test cross, an organism with the dominant phenotype is crossed with an organism that is homozygous recessive for the same characteristic. If the dominant-expressing organism is a homozygote, then all offspring will be heterozygotes expressing the dominant trait. Alternatively, if the dominant expressing organism is a heterozygote, the offspring will exhibit a 1:1 ratio of heterozygotes and recessive homozygotes.