Question

If a test cross of a tall plant of unknown genotype results in half tall offspring and half dwarf offspring, what is the genotype of the unknown parent?

Options

• \([tt]\) (Homozygous recessive)

• Hemizygous dominant

• \([TT]\) (Homozygous dominant)

• \([Tt]\) (Heterozygous)

Answer 1

In a test cross with \([tt]\), if the unknown parent is heterozygous \([Tt]\), the cross \([Tt] \times [tt]\) produces \(50\%\) tall \([Tt]\) and \(50\%\) dwarf \([tt]\) offspring. If it were homozygous \([TT]\), all offspring would be tall.