Question

Independent assortment of genes does not takes place when
A. Genes are located on homologous chromosomes.
B. Genes are linked and located on the same chromosome.
C. Genes are located on non-homologous chromosomes.
D. All of the above.

Answer 1

Hint: Gregor Johann Mendel, an Austrian monk, scientist, mathematician, meteorologist as well as the first systematic researcher in the field of genetics was often regarded as the ‘Father of Genetics’. Through his experiments and studies, he uncovered the mysteries and key principles of heredity as well as proposed the three fundamental laws of inheritance.

Complete answer:
Between 1856 and 1863, Mendel conducted experiments on Plant Hybridization by cultivating and testing garden pea plants (Pisum sativum). Based on his studies and experiments, he formulated three laws of inheritance of traits namely – Law of Dominance, Law of Segregation and Law of Independent Assortment.
According to Mendel’s law of independent assortment, alleles of two or more different genes are separated and segregated independently of another during gamete formation in order to produce both parental and new combinations.
A well-known example for the law of independent assortment is Mendelian dihybrid cross (crossing of two pairs of traits). When two alleles of different pairs of traits are self-crossed, then it will obtain four different traits independent of one another.
Therefore, when genes are linked and located on the same chromosome then the independent assortment of genes does not take place.

Hence, the correct answer is option (B).

Note: In Mendel’s Law of Inheritance, the only law which has been accepted universally without any exception is the Law of segregation. It is also referred to as the Law of purity of gametes. According to this law, it states that each trait or hereditary factor consists of two alleles which get segregated during the production and formation of gametes and one allele from each parent combines and re-unite randomly during fertilization.