Concept explainers
Production of more than one
- a. pleiotrofy.
- b. genetic determinism.
- c. codominance.
- d. penetrance.
- e. genetic recombination
Introduction:
A single gene is responsible for the production of multiple phenotypes and this is termed as a pleiotropic effect. The gene influences multiple traits of organisms, which may transfer from one generation to another. In humans, phenylketonuria (PKU) is associated with pleiotropy. Phenylalanine hydroxylase converts phenylalanine to tyrosine; the mutation in phenylalanine hydroxylase encoding genes leads to multiple traits associated with phenylketonuria. It causes mental disorders, pigment defects, and eczema.
Answer to Problem 1TYR
Correct answer:
A single gene influences multiple or more than a phenotypic trait and is known as pleiotropy. Therefore, option a is correct.
Explanation of Solution
Justify reasons for the correct statement:
A single gene produces numerous phenotypic traits and is called as pleiotropy.
Option (a) is given as “pleiotropy”.
Multiple phenotypic characters produced by a gene is known as pleiotropy.
Hence, option (a) is correct.
Justify reasons for the incorrect statements:
Option (b) is given as “genetic determinism”.
Controlling of race, sex, and mental health by genes is known as genetic determinism. Hence, it is a wrong answer.
Option (c) is given as “codominance”.
Expression of both alleles of a gene in an organism is known as codominance. Hence, it is a wrong answer.
Option (d) is given as “penetrance”.
Exhibition of expected phenotype from the percentage of the given genotype is known as penetrance. Hence, it is a wrong answer.
Option (e) is given as “genetic recombination”.
Exchange of genetic material between two chromosomes or a different location of a single chromosome is known as genetic recombination. Hence, it is a wrong answer.
Hence, options (b), (c), (d), and (e) are incorrect.
A single gene produces numerous phenotypic traits and is called as pleiotropy.
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