Question

Test cross is used to confirm ________ .

• A. phenotype of the organism with dominant expression.
• B. sex gender of an organism.
• C. genotype of the organism with dominant expression.
• D. genotype ratio in $F_2$ generation.

Hint:

Test cross = Dominant × Recessive to reveal hidden genotype.

Answer 1

The Correct Option is C

Concept:
A test cross is performed to determine the genotype of an individual showing a dominant phenotype.

Step 1: Define test cross. It involves crossing an individual with dominant phenotype with a homozygous recessive individual. \[ \text{Test cross: } (A\_) \times (aa) \]

Step 2: Interpret outcomes.
• All dominant offspring → Homozygous dominant (AA)
• 1:1 ratio → Heterozygous (Aa)

Step 3: Analyze options.
• (A) Phenotype → Already known $\times$
• (B) Sex determination → Not related $\times$
• (C) Genotype of dominant organism → Correct \checkmark
• (D) Genotype ratio in F$_2$ → Not purpose $\times$

Step 4: Conclusion. \[ \text{Test cross determines genotype of dominant individual} \]