Question

In a test cross, which parent must always be used alongside the dominant phenotype individual?

Options

• Any parent with unknown genotype

• Homozygous dominant (TT)

• Homozygous recessive (tt)

• Heterozygous dominant (Tt)

Answer 1

By definition, a test cross always involves crossing the individual with the dominant phenotype with a homozygous recessive (tt) parent. This allows the recessive alleles to be expressed in the offspring, revealing the genotype of the dominant parent.