Textbook Question
A strain of E. coli is identified as having a null mutation of the RecA gene. What biological property do you expect to be absent in the mutant strain? What is the molecular basis for the missing property?
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Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
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Table of contents
- Ch. 1 - The Molecular Basis of Heredity, Variation, and Evolution64
- Ch. 2 - Transmission Genetics144
- Ch. 3 - Cell Division and Chromosome Heredity81
- Ch. 4 - Gene Interaction87
- Ch. 5 - Genetic Linkage and Mapping in Eukaryotes103
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages73
- Ch. 7 - DNA Structure and Replication71
- Ch. 8 - Molecular Biology of Transcription and RNA Processing79
- Ch. 9 - The Molecular Biology of Translation110
- Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization100
- Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination86
- Ch. 12 - Regulation of Gene Expression in Bacteria and Bacteriophage90
- Ch. 13 - Regulation of Gene Expression in Eukaryotes38
- Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics72
- Ch. 15 - Recombinant DNA Technology and Its Applications69
- Ch. 16 - Genomics: Genetics from a Whole-Genome Perspective49
- Ch. 17 - Organelle Inheritance and the Evolution of Organelle Genomes27
- Ch. 18 - Developmental Genetics43
- Ch. 19 - Genetic Analysis of Quantitative Traits66
- Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels105
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
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Sanders 3rd EditionCh. 11 - Gene Mutation, DNA Repair, and Homologous RecombinationProblem 19a
Sanders 3rd EditionCh. 11 - Gene Mutation, DNA Repair, and Homologous RecombinationProblem 19aChapter 11, Problem 19a
Using the adenine–thymine base pair in this DNA sequence
...GCTC...
...CGAG...
Give the sequence after a transition mutation.
Verified step by step guidance1
Step 1: Understand the concept of a transition mutation. A transition mutation is a type of point mutation where a purine (adenine or guanine) is replaced with another purine, or a pyrimidine (cytosine or thymine) is replaced with another pyrimidine.
Step 2: Analyze the provided DNA sequence before the mutation. The original sequence is: CCTTAGGATTCC (top strand) and GGAATCCTAAGG (bottom strand).
Step 3: Observe the mutation in the image. The sequence changes from CCTTAGGATTCC to CCTCAGGATTCC (top strand) and GGAATCCTAAGG to GGAGTCCTAAGG (bottom strand).
Step 4: Identify the specific base pair affected by the transition mutation. In the top strand, the second 'T' in the sequence changes to 'C', and in the bottom strand, the corresponding 'A' changes to 'G'. This is consistent with a transition mutation.
Step 5: Write the mutated sequence. After the transition mutation, the new sequence is: CCTCAGGATTCC (top strand) and GGAGTCCTAAGG (bottom strand).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Transition Mutation
A transition mutation is a specific type of point mutation where a purine base (adenine or guanine) is replaced by another purine, or a pyrimidine base (cytosine or thymine) is replaced by another pyrimidine. This type of mutation can lead to changes in the amino acid sequence of proteins, potentially affecting their function. In the provided example, the mutation changes a 'C' to a 'T', illustrating this concept.
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Point Mutations
DNA Base Pairing
DNA base pairing refers to the specific pairing of nitrogenous bases in the DNA double helix, where adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G). This complementary base pairing is crucial for DNA replication and transcription, ensuring genetic information is accurately passed on. Understanding base pairing is essential for analyzing mutations, as changes in one base can affect the entire sequence.
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Effects of Mutations
Mutations can have various effects on an organism, ranging from benign to harmful. They can alter protein structure and function, potentially leading to diseases or changes in traits. In the context of the question, understanding how a transition mutation affects the DNA sequence helps predict the potential impact on the resulting protein and the organism's phenotype.
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Related Practice
Textbook Question
Describe the difference between DNA transposons and retrotransposons.
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Textbook Question
How are flanking direct repeat sequences created by transposition?
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Textbook Question
Using the adenine–thymine base pair in this DNA sequence
...GCTC...
...CGAG...
Give the sequence after a transversion mutation.
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Textbook Question
The partial amino acid sequence of a wild-type protein is
… Arg-Met-Tyr-Thr-Leu-Cys-Ser …
The same portion of the protein from a mutant has the sequence
… Arg-Met-Leu-Tyr-Ala-Leu-Phe …
Identify the type of mutation.
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Textbook Question
The partial amino acid sequence of a wild-type protein is
… Arg-Met-Tyr-Thr-Leu-Cys-Ser …
The same portion of the protein from a mutant has the sequence
… Arg-Met-Leu-Tyr-Ala-Leu-Phe …
Give the sequence of the wild-type DNA template strand. Use A/G if the nucleotide could be either purine, T/C if it could be either pyrimidine, N if any nucleotide could occur at a site, or the alternative nucleotides if a purine and a pyrimidine are possible.
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