Question

Define and design a test-cross.

Answer 1

Test cross:

1. Test-cross is an experiment in which an organism showing dominance for a specific trait has to be tested for its genotype.
2. When an organism shows a dominant character, it could be homozygous or heterozygous for that character.
   
3. Using the homozyous recessive organism, the genotype of the organism can be tested.
   

Design of a test cross:

1. Test-cross between pure dominant (A) and hybrid dominant (B) individuals with the recessive parent are shown below:

1. The condition clearly depicts that depicts that of the genotype of the organism is homozygous dominant, all the offspring of the test cross will have the dominant phenotype.
   
2. If the genotype of the organism is heterozygous, then the offspring of the test cross will have half having the dominant and half having the recessive character. ​