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Which one of the following is a wrong statement regarding mutations?
A
Change in a single base pair of DNA does not cause mutation
B
Deletion and insertion of base pairs cause frame-shift mutations
C
Cancer cells commonly show chromosomal aberrations
D
UV and Gamma rays are mutagens
Detailed Solution
A mutation is a change in the DNA sequence that alters the genotype and phenotype.
A change in even a single base pair of DNA is a mutation, called a point mutation. The classical example is sickle-cell anaemia, in which a single base substitution (GAG → GUG in the codon) replaces glutamic acid by valine in the $\beta$-globin chain.
So the statement that a single base pair change does not cause mutation is wrong.
Deletions and insertions of base pairs shift the reading frame and cause frame-shift mutations (true).
Chromosomal aberrations are commonly observed in cancer cells (true), and UV and gamma radiations are physical mutagens (true).
Hence the wrong statement is 'Change in a single base pair of DNA does not cause mutation'.
A change in even a single base pair of DNA is a mutation, called a point mutation. The classical example is sickle-cell anaemia, in which a single base substitution (GAG → GUG in the codon) replaces glutamic acid by valine in the $\beta$-globin chain.
So the statement that a single base pair change does not cause mutation is wrong.
Deletions and insertions of base pairs shift the reading frame and cause frame-shift mutations (true).
Chromosomal aberrations are commonly observed in cancer cells (true), and UV and gamma radiations are physical mutagens (true).
Hence the wrong statement is 'Change in a single base pair of DNA does not cause mutation'.