Textbook Question
What is the difference between a silent mutation and a neutral mutation?
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Ch. 14 - Gene Mutation, DNA Repair, and Transposition
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
Chapter 14, Problem 11
Why are frameshift mutations likely to be more detrimental than point mutations, in which a single pyrimidine or purine has been substituted?
Verified step by step guidance1
Understand the nature of point mutations: these involve the substitution of a single nucleotide base (a purine or pyrimidine) with another, which may or may not change the amino acid sequence due to the redundancy of the genetic code.
Recognize that frameshift mutations occur when nucleotides are inserted or deleted in numbers not divisible by three, causing a shift in the reading frame of the mRNA during translation.
Analyze how the reading frame shift alters the grouping of codons downstream of the mutation, potentially changing every amino acid encoded after the mutation site.
Consider the consequences of this shift: it often leads to the production of a completely different and usually nonfunctional protein, or introduces premature stop codons that truncate the protein.
Compare this to point mutations, which may only affect a single amino acid or sometimes have no effect at all (silent mutations), explaining why frameshift mutations are generally more detrimental.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Frameshift Mutations
Frameshift mutations occur when nucleotides are inserted or deleted from the DNA sequence, altering the reading frame of the gene. This shift changes every codon downstream, often resulting in a completely different and nonfunctional protein. Because the entire amino acid sequence is affected, frameshift mutations tend to have severe consequences.
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Point Mutations
Point Mutations
Point mutations involve the substitution of a single nucleotide base, such as replacing one purine or pyrimidine with another. These mutations may cause a silent, missense, or nonsense change, often affecting only one amino acid or sometimes none, making their impact generally less severe than frameshift mutations.
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09:49Point Mutations
Genetic Code and Reading Frame
The genetic code is read in triplets called codons, each coding for a specific amino acid. Maintaining the correct reading frame is crucial for producing functional proteins. Frameshift mutations disrupt this frame, while point mutations usually do not, explaining why frameshifts are more detrimental.
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Related Practice
Textbook Question
Describe a tautomeric shift and how it may lead to a mutation.
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Textbook Question
Contrast and compare the mutagenic effects of deaminating agents, alkylating agents, and base analogs.
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Textbook Question
Why are X rays more potent mutagens than UV radiation?
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Textbook Question
Contrast the various types of DNA repair mechanisms known to counteract the effects of UV radiation. What is the role of visible light in repairing UV-induced mutations?
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Textbook Question
Mammography is an accurate screening technique for the early detection of breast cancer in humans. Because this technique uses X rays diagnostically, it has been highly controversial. Can you explain why? What reasons justify the use of X rays for such a medical screening technique?
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