Question

Which of the following is a test cross?

• A. Ww $\times$ ww
• B. WW $\times$ ww
• C. ww $\times$ WW
• D. All of the above

Answer 1

The correct option is D All of the above

A cross between two organisms, one of which has an unknown genotype and the other with a homozygous recessive trait is called a test cross. This cross was first performed by Gregor Mendel and is used to detect the unknown genotype of a particular organism. Hence it is a valuable tool in genetics. In all the given options the cross involves a homozygous recessive genotype ww. Thus the correct answer is option D.