GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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a base insertion only.
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a base substitution only.
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a base deletion only.
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either an insertion or deletion of a base.
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Detailed explanation-1: -A frameshift mutation in a gene refers to the insertion or deletion of nucleotide bases in numbers that are not multiples of three. This is important because a cell reads a gene’s code in groups of three bases when making a protein.
Detailed explanation-2: -An insertion or deletion involving a number of base pairs that is not a multiple of three, which consequently disrupts the triplet reading frame of a DNA sequence.
Detailed explanation-3: -Frameshift mutations arise when the normal sequence of codons is disrupted by the insertion or deletion of one or more nucleotides, provided that the number of nucleotides added or removed is not a multiple of three.
Detailed explanation-4: -A frameshift mutation is produced either by insertion or deletion of one or more new bases. Because the reading frame begins at the start site, any mRNA produced from a mutated DNA sequence will be read out of frame after the point of the insertion or deletion, yielding a nonsense protein.
Detailed explanation-5: -C is correct. Insertion or deletion of three (or multiples of 3) nucleotides does not result in a frameshift mutation. It only results in the presence (or absence) of some amino acids in the polypeptide.