Q. Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration, is called :

Q. Mating of an organism to a double recessive in order to determine whether it is homozygous or heterozygous for a character under consideration, is called :

(a) Reciprocal cross

(b) Test cross

(c) Dihybrid cross

(d) Back cross

Solution :

Correct option : B Two crosses between the same pair of genotypes/phenotypes in which the sources of gametes are reversed in one cross are called a reciprocal cross. It is performed to confirm if the results of the cross are affected by the sex of parents and does not necessarily involve one double recessive parent. A test cross is performed to determine the genotype of a dominant parent if it is a heterozygous- or homozygous-dominant. For the purpose, a dominant parent is crossed with the homozygous recessive parent. Thus, the correct answer is option B.