Question

Which mendelian principle will not operate if two genes under study are close together
A. Paired unit factors
B. Dominance
C. Segregation
D. Independent assortment

Answer 1

Mendel studied the operation of one gene in a monohybrid cross of a pea plant and concluded on the law of segregation. Secondly, he studied the operation of two genes on the same species and concluded on the law of independent assortment.

Step by step answer:
When a dihybrid cross is made between two individuals that are different from each other in two or more characters – the inheritance of one character is fully independent to the inheritance of another character. This is the main idea of the Law of independent assortment.
The idea was first introduced by Mendel. This is only applicable when the genes are present on two different chromosomes. if these genes are present closely on the same chromosome, they will not show independent assortment.
Hence, the correct answer is option D, i.e., Independent assortment

Note: Dominance can be described as the phenomenon in which an individual that contains two allelic forms of a gene – one is expressed fully eliminating the effect of the other. Segregation can be defined as the separation of pairs of alleles during meiotic cell division and their independent transmission through separate gametes. Paired unit factors or paired unit genes can be described as a pair of specific unit factors that exist for each trait, for example tall gene and the dwarf gene for the height of a species. Each diploid individual has two-unit factors – one inherited from mother and one from father.