The phenomenon of pleiotropism refers to [2023]
a single gene affecting multiple phenotypic expression
more than two genes affecting a single character
presence of several alleles of a single gene controlling a single crossover
presence of two alleles, each of the two genes controlling a single trait
(1)
Pleiotropy is a phenomena where a single gene can exhibit multiple phenotypic expression. Such a gene is called a pleiotropic gene.
Match the terms in column I with their description in column II and choose the correct option. [2016]
| Column I | Column II | ||
| A. | Dominance | (i) | Many genes govern a single character |
| B. | Co-dominance | (ii) | In a heterozygous organism only one allele expresses itself |
| C. | Pleiotropy | (iii) | In a heterozygous organism both alleles express themselves fully |
| D. | Polygenic | (iv) | A single gene inheritance influences many characters |
A-(iv), B-(i), C-(ii), D-(iii)
A-(iv), B-(iii), C-(i), D-(ii)
A-(ii), B-(i), C-(iv), D-(iii)
A-(ii), B-(iii), C-(iv), D-(i)
A pleiotropic gene [2015]
controls a trait only in combination with another gene
controls multiple traits in an individual
is expressed only in primitive plants
is a gene evolved during Pliocene
(2)
The ability of a gene to have multiple phenotypic effects because it influences a number of characters simultaneously is known as pleiotropy. The gene having a multiple phenotypic effect because of its ability to control expression of two or more characters is called pleiotropic gene. In human beings pleiotropy is exhibited by syndromes called sickle cell anaemia and phenylketonuria.
