EBK CONCEPTS OF GENETICS
12th Edition
ISBN: 9780134818979
Author: Killian
Publisher: YUZU
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Textbook Question
Chapter 24, Problem 28ESP
The table in this problem summarizes some of the data that have been collected on mutations in the BRCA1 tumor-suppressor gene in families with a high incidence of both early-onset breast cancer and ovarian cancer.
Predisposing Mutations in BRCA1
*NA indicates not applicable, as the regulatory mutation is inferred and the position has not been identified.
- (a) Note the coding effect of the mutation found in kindred group 2082. This results from a single base-pair substitution. Draw the normal double-stranded DNA sequence for this codon (with the 5′ and 3′ ends labeled), and show the sequence of events that generated this mutation, assuming that it resulted from an uncorrected mismatch event during
DNA replication. - (b) Examine the types of mutations that are listed in the table, and determine if the BRCA1 gene is likely to be a tumor-suppressor gene or an oncogene.
- (c) Although the mutations listed in the table are clearly deleterious and cause breast cancer in women at very young ages, each of the kindred groups had at least one woman who carried the mutation but lived until age 80 without developing cancer. Name at least two different mechanisms (or variables) that could underlie variation in the expression of a mutant
phenotype , and propose an explanation for the incomplete penetrance of this mutation. How do these mechanisms or variables relate to this explanation?
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Chapter 24 Solutions
EBK CONCEPTS OF GENETICS
Ch. 24 - Prob. 1NSTCh. 24 - People with a genetic condition known as...Ch. 24 - Prob. 3NSTCh. 24 - Cancer can arise spontaneously, but it can also be...Ch. 24 - Prob. 1CSCh. 24 - Prob. 2CSCh. 24 - If you agree to participate and then learn that...Ch. 24 - HOW DO WE KNOW? In this chapter, we focused on...Ch. 24 - Prob. 2PDQCh. 24 - Where are the major regulatory points in the cell...
Ch. 24 - List the functions of kinases and cyclins, and...Ch. 24 - How can mutations in noncoding segments of DNA...Ch. 24 - What is the difference between saying that cancer...Ch. 24 - Prob. 7PDQCh. 24 - Prob. 8PDQCh. 24 - Define tumor-suppressor genes. Why is a mutated...Ch. 24 - Describe the steps by which the TP53 gene responds...Ch. 24 - Part of the Ras protein is associated with the...Ch. 24 - Prob. 12PDQCh. 24 - Distinguish between oncogenes and proto-oncogenes....Ch. 24 - Prob. 14PDQCh. 24 - How do translocations such as the Philadelphia...Ch. 24 - Explain why many oncogenic viruses contain genes...Ch. 24 - Prob. 17PDQCh. 24 - How do normal cells protect themselves from...Ch. 24 - Prob. 19PDQCh. 24 - Epigenetics is a relatively new area of genetics...Ch. 24 - Radiotherapy (treatment with ionizing radiation)...Ch. 24 - Genetic tests that detect mutations in the BRCA1...Ch. 24 - Explain the apparent paradox that both...Ch. 24 - As part of a cancer research project, you have...Ch. 24 - Mutations in tumor-suppressor genes are associated...Ch. 24 - Prob. 26ESPCh. 24 - Those who inherit a mutant allele of the RB1...Ch. 24 - The table in this problem summarizes some of the...Ch. 24 - Researchers have identified some tumors that have...Ch. 24 - Prob. 30ESP
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- mice were treated with a virus that inhibited expression of angiopoietin 2, MMP3 and MMP10 in the lung or with a control virus (Mock). Breast cancer cells that express the gene luciferase were then injected into the mammary glands of the mice. The metstasis of the tumors to the lungs could then be measured by imaging the presence of luciferase in the lungs. In 5-6 sentences, explain the data below and why knockout of Angpt2, MMP3 and MMP10 appears to inhibit metstastasis.arrow_forwardGenetic tests that detect mutations in the BRCA1 and BRCA2 oncogenes are widely available. These tests reveal a number of mutations in these genes—mutations that have been linked to familial breast cancer. Assume that a young woman in a suspected breast cancer family takes the BRCA1 and BRCA2 genetic tests and receives negative results. That is, she does not test positive for the mutant alleles of BRCA1 or BRCA2. Can she consider herself free of risk for breast cancer?arrow_forwardCD3 is a signaling protein that is typically found only in the plasma membrane of immune system T lymphocytes. CD3 is composed of several different polypeptides, including a gamma chain, CD3γ. Scientists analyzed the promoter of the CD3γ chain gene for regulatory sequences that might have positive or negative effects on expression of the gene. The scientists cloned fragments of the CD3γ gene that included the first transcribed nucleotides plus up to 789 nucleotides of upstream regulatory sequences into plasmids in which the gene for the firefly enzyme luciferase immediately follows the fragments. The plasmids were then introduced into a line of T lymphocytes (Figure 1), and the cells were allowed to grow for a short while. Because the regulatory sequences of the CD3γ gene immediately precede the luciferase gene in the plasmids, the activity, either positive or negative, of the regulatory sequences affected the amount of luciferase gene expression by the T lymphocytes. Luciferase…arrow_forward
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