Question

What is the genotypic and phenotypic ratio of the monohybrid test cross?

• A. $2:1$
• B. $1:2$
• C. $1:1$
• D. $2:1:1$

Answer 1

The correct option is C

$1:1$

The correct option is C

Explanation of the correct option:

1. A cross made between hybrid and homozygous recessive individuals is called a test cross.
2. It is used to determine whether it is homozygous or heterozygous.
3. In test cross 50% of offspring are heterozygous, and 50% of offspring are homozygous recessive.
4. Test cross:

$$\begin{gathered} \mathrm{Hybrid}\mathrm{tall}\times \mathrm{recessive}\mathrm{dwarf} \\ \mathrm{Tt}\times \mathrm{tt} \\ \mathrm{Offspring}:\mathrm{Tt}\mathrm{and}\mathrm{tt} \\ \mathrm{Phenotypic}\mathrm{ratio}:1:1 \\ \mathrm{Genotypic}\mathrm{ratio}:1:1 \end{gathered}$$

Final answer: The genotypic and phenotypic ratio of the monohybrid test cross is 1:1.