Textbook Question
Based on what you read in this chapter, Can a tumor arise from a single mutated cell? Are all the cells in a tumor identical?
Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics
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. 14 - Analysis of Gene Function via Forward Genetics and Reverse GeneticsProblem C.8a
Sanders 3rd EditionCh. 14 - Analysis of Gene Function via Forward Genetics and Reverse GeneticsProblem C.8aChapter 14, Problem C.8a
The inheritance of certain mutations of BRCA1 can make it much more likely that a woman will develop breast or ovarian cancer in her lifetime. Can you say with certainty that a woman inheriting a mutation of BRCA1 will definitely develop breast or ovarian cancer in her lifetime? Why or why not?
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Understand that inheriting a mutation in the BRCA1 gene increases the risk of developing breast or ovarian cancer, but it does not guarantee that cancer will develop. This is because BRCA1 mutations are considered risk factors, not deterministic causes.
Recognize the concept of penetrance in genetics, which refers to the proportion of individuals with a particular genetic mutation who actually express the associated trait or disease. BRCA1 mutations have incomplete penetrance.
Consider environmental factors, lifestyle, and other genetic factors that can influence whether a woman with a BRCA1 mutation will develop cancer. These factors interact with the mutation to affect cancer risk.
Note that genetic counseling and testing provide probabilities or risk assessments rather than certainties, reflecting the complex nature of gene-environment interactions.
Summarize that while a BRCA1 mutation significantly raises the likelihood of cancer, it is not a definitive predictor, so a woman inheriting the mutation may or may not develop breast or ovarian cancer during her lifetime.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
BRCA1 Gene and Its Role
BRCA1 is a gene that produces proteins responsible for repairing DNA damage. Mutations in BRCA1 can impair this repair process, increasing the risk of developing breast and ovarian cancers. However, not all mutations have the same effect, and the presence of a mutation raises risk but does not guarantee cancer.
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Segmentation Genes
Genetic Penetrance
Penetrance refers to the proportion of individuals with a specific genetic mutation who actually express the associated trait or disease. In the case of BRCA1 mutations, penetrance is incomplete, meaning some women with the mutation may never develop cancer, while others do, due to various genetic and environmental factors.
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02:09Penetrance and Expressivity
Risk Factors and Multifactorial Inheritance
Cancer development is influenced by multiple factors beyond a single gene mutation, including lifestyle, environment, and other genetic variations. Thus, inheriting a BRCA1 mutation increases risk but does not act alone, making cancer a multifactorial disease where risk is probabilistic, not deterministic.
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05:13Organelle Inheritance
Related Practice
Textbook Question
Describe how CRISPR–Cas has been modified to create a genome-editing tool.
Textbook Question
Do you think it is important that participation in community-based genetic screening be entirely voluntary? Why or why not?
Textbook Question
The inheritance of certain mutations of BRCA1 can make it much more likely that a woman will develop breast or ovarian cancer in her lifetime. In addition to inheriting a BRCA1 mutation, what else must happen for a woman to develop breast or ovarian cancer?
Textbook Question
Discuss the advantages (and possible disadvantages) of the different approaches to reverse genetics.
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Textbook Question
Go to the website http://www.cancer.gov and select 'Cancer Types' on the top menu bar. Scroll down to 'Breast Cancer' and click. Select 'Cases & Prevention' from the options. Click 'More information' and select 'BRCA Mutations: Cancer Risk and Genetic Testing'. Use the information on this page to answer the following questions. With regard to the results of genetic testing for BRCA1 and BRCA2 mutations, what is meant by a 'positive result'?