Directions : (21 - 25) |
Read the passage given below and answer the following questions. |
We have so far seen the effect of a gene on a single phenotype or trait. There are however instances where a single gene can exhibit multiple phenotypic expression. Such a gene is called a pleiotropic gene. The underlying mechanism of pleiotropy in most cases is the effect of a gene on metabolic pathways which contributes towards different phenotypes. An example of this is the disease phenylketonuria (PKU; Foiling, 1934) which occurs in humans. The disease is caused by mutation in the gene that codes for the enzyme phenyl alanine hydroxylase i.e., single gene mutation. Pleiotropism is defined as a phenomenon when single gene may produce more than one effect i.e., the multiple effect of a gene or control several phenotypes depending on its position. This results in a phenotypic expression characterized by mental retardation and a reduction in hair and skin pigmentation (albinism). In Drosophila white eye mutation leads to depigmentation in many other parts of the body, giving a pleiotropic effect. In transgenic organisms, the introduced gene can produce different effects depending on where the gene has introgressed. |
A) Monogene
B) Polygenes
C) Pleiotropic
D) Digenes
Correct Answer: C
Solution :
PleiotropicYou need to login to perform this action.
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