Genetics: Analysis and Principles
6th Edition
ISBN: 9781259616020
Author: Robert J. Brooker Professor Dr.
Publisher: McGraw-Hill Education
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Chapter 25, Problem 9CONQ
Ehler-Danlos syndrome is a rare disorder caused by a mutation in a gene that encodes a protein called collagen (type 3 A1). Collagen is found in the extracellular matrix that plays an important role in the formation of skin, joints, and other connective tissues. People with Ehler-Danlos syndrome have extraordinarily flexible skin and very loose joints. The pedigree below contains several individuals affected with this syndrome, shown with black symbols. Based on this pedigree, does the syndrome appear to follow autosomal recessive, autosomal dominant, X-linked recessive, or X-linked dominant inheritance? Explain your reasoning.
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Ehler-Danlos syndrome is a rare disorder caused by a mutation ina gene that encodes a protein called collagen (type 3 A1). Collagenis found in the extracellular matrix that plays an important role inthe formation of skin, joints, and other connective tissues. Peoplewith Ehler-Danlos syndrome have extraordinarily flexible skin andvery loose joints. The following pedigree contains several individualsaffected with this syndrome, shown with black symbols. Basedon this pedigree, does the syndrome follow autosomal recessive,autosomal dominant, X-linked recessive, or X-linked dominantinheritance? Explain your reasoning.
Lesch-Nyhan syndrome is due to a mutation in a gene that encodesa protein called hypoxanthine-guanine phosphoribosyltransferase(HPRT). HPRT is an enzyme that functions in purine metabolism.People afflicted with this syndrome have severe neurodegenerationand loss of motor control. The pedigree below contains severalindividuals with Lesch-Nyhan syndrome, shown with blacksymbols. Based on this pedigree, does this syndrome appearto be inherited by an autosomal recessive, autosomal dominant,X-linked recessive, or X-linked dominant pattern? Explainyour reasoning.
Junctional epidermolysis bullosa (JEB) is a severe skin disorder that results in blisters over the entire body. The disorder is caused by autosomal recessive mutations at any one of three loci that help to encode laminin 5, a major component in the dermal–epidermal basement membrane. Leena Pulkkinen and colleagues described a male newborn who was born with JEB and died at 2 months of age (L. Pulkkinen et al. 1997. American Journal of Human Genetics 61:611–619); the child had healthy, unrelated parents. Chromosome analysis revealed that the infant had 46 normal-appearing chromosomes. Analysis of DNA showed that his mother was heterozygous for a JEB-causing allele at the LAMB3 locus, which is on chromosome 1. The father had two normal alleles at this locus. DNA fingerprinting demonstrated that the male assumed to be the father had, in fact, conceived the child.
Q. Assuming that no new mutations occurred in this family, explain the presence of an autosomal recessive disease in the child…
Chapter 25 Solutions
Genetics: Analysis and Principles
Ch. 25.1 - Which of the following wouldnotbe consistent with...Ch. 25.1 - 2. Assuming complete penetrance, which type of...Ch. 25.1 - 3. Which of the following is not a common...Ch. 25.1 - Prob. 4COMQCh. 25.2 - Prob. 1COMQCh. 25.2 - Haplotype association studies are aimed at the...Ch. 25.3 - 1. Which of the following is not a method used in...Ch. 25.3 - 2. Which of the following prenatal genetic testing...Ch. 25.4 - Prob. 1COMQCh. 25.5 - 1. An oncogene is produced from a ________that has...
Ch. 25.5 - Which of the following is a type of genetic change...Ch. 25.5 - 3. Tumor-suppressor genes promote cancer...Ch. 25.5 - 4. Normal (nonmutant) tumor-suppressor genes often...Ch. 25.5 - Prob. 5COMQCh. 25.6 - Prob. 1COMQCh. 25 - 1. With regard to pedigree analysis, make a list...Ch. 25 - 2. Explain, at the molecular level, why human...Ch. 25 - 3. Many genetic disorders exhibit locus...Ch. 25 - Prob. 4CONQCh. 25 - Prob. 5CONQCh. 25 - Figure 25.1 illustrates albinism in two different...Ch. 25 - Prob. 7CONQCh. 25 - Prob. 8CONQCh. 25 - Ehler-Danlos syndrome is a rare disorder caused by...Ch. 25 - 10. Hurler syndrome is due to a mutation in a gene...Ch. 25 - Like Hurler syndrome, Fabry disease involves an...Ch. 25 - Achondroplasia is a rare form of dwarfism caused...Ch. 25 - Prob. 13CONQCh. 25 - 14. Marfan syndrome is due to a mutation in a...Ch. 25 - 15. Sandhoff disease is due to a mutation in a...Ch. 25 - Describe the two assumptions that underlie the...Ch. 25 - Prob. 17CONQCh. 25 - What is a prion? Explain how a prion relies on...Ch. 25 - 19. Some people have a genetic predisposition for...Ch. 25 - What is the difference between an oncogene and a...Ch. 25 - Prob. 21CONQCh. 25 - Prob. 22CONQCh. 25 - Prob. 23CONQCh. 25 - Prob. 24CONQCh. 25 - Prob. 25CONQCh. 25 - Prob. 26CONQCh. 25 - Prob. 27CONQCh. 25 - With regard to cancer cells, which of the...Ch. 25 - Prob. 29CONQCh. 25 - 1. Which of the following experimental...Ch. 25 - Prob. 2EQCh. 25 - 3. What is meant by the term genetic testing? How...Ch. 25 - Prob. 4EQCh. 25 - 5. Chapter 21 describes a method known as Western...Ch. 25 - 6. An experimental assay for the blood-clotting...Ch. 25 - 7. Discuss ways to distinguish whether a...Ch. 25 - 8. The codon change (Gly-12 to Val-12) in...Ch. 25 - Explain how DNA microarrays are used in molecular...Ch. 25 - Make a list of the benefits that may arise from...Ch. 25 - 2. Our government has finite funds to devote to...Ch. 25 - Prob. 3QSDC
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- Sandhoff disease is due to a mutation in a gene that encodes a proteincalled hexosaminidase B. This disease has symptoms that aresimilar to those of Tay-Sachs disease. Weakness begins in the first 6 months of life. Individuals exhibit early blindness and progressive mental and motor deterioration. The family in the pedigree shown below has three members with Sandhoff disease, indicated with black symbols.arrow_forwardJunctional epidermolysis bullosa (JEB) is a severe skin disorder that results in blisters over the entire body. The disorder is caused by autosomal recessive mutations at any one of three loci that help to encode laminin 5, a major component in the dermal–epidermal basement membrane. Leena Pulkkinen and colleagues described a male newborn who was born with JEB and died at 2 months of age (L. Pulkkinen et al. 1997. American Journal of Human Genetics 61:611–619); the child had healthy, unrelated parents. Chromosome analysis revealed that the infant had 46 normal-appearing chromosomes. Analysis of DNA showed that his mother was heterozygous for a JEB-causing allele at the LAMB3 locus, which is on chromosome 1. The father had two normal alleles at this locus. DNA fingerprinting demonstrated that the male assumed to be the father had, in fact, conceived the child. Q. How might you go about proving your explanation? Assume that a number of genetic markers are available for each chromosome.arrow_forwardDuchenne Muscular Dystrophy (DMD) is a disorder that primarily affects the function of skeletal muscles used for movement and cardiac muscles used for heart beating. Dystrophin is a protein encoded by a single gene, DMD, that is expressed in skeletal and cardiac muscle. Some forms of muscular dystrophy may be caused by different mutations in the DNA sequence of the DMD gene. Because the DMD locus is on the X chromosome, males are affected at higher rates. Two brothers, one of whom has DMD and one of whom does not, worked with their genetic counselor (Links to an external site.) to have their DMD gene sequenced to identify genetic variation that may explain why one brother was affected and the other not. Because DMD is a very long gene, a fictionalized, simplified model of the results is presented here (Figure 1). The actual DMD mRNA is about 16,000 base-pairs!------Consider single nucleotide polymorphism (SNP) #1 (Figure 1). Is this mutation likely to cause Duchenne muscular…arrow_forward
- Achondroplasia is an autosomal dominant disorder characterized by disproportionate short stature: the legs and arms of people with achondroplasia are short compared with the head and trunk. The disorder is due to a base substitution in the gene, located on the short arm of chromosome 4, that encodes fibroblast growth factor receptor 3 (FGFR3). Although achondroplasia is clearly inherited as an autosomal dominant trait, more than 80% of the people who have achondroplasia are born to parents with normal stature. This high percentage indicates that most cases are caused by newly arising mutations; these cases (not inherited from an affected parent) are referred to as sporadic. Studies have demonstrated that sporadic cases of achondroplasia are almost always caused by mutations inherited from the father (paternal mutations). In addition, the occurrence of achondroplasia is higher among the children of older fathers; approximately 50% of children with achondroplasia are born to fathers…arrow_forwardIn McCune-Albright syndrome, fibrous connective tissue replaces bone, tan patches (café-au-lait spots) dot the skin, and hormone abnormalities cause early puberty and malfunction of the thyroid, pituitary, and adrenal glands. The phenotype is highly variable, and all patients are somatic mosaics for the mutation, which is in the gene GNAS1. Why is the condition seen only in mosaics?arrow_forwardBRCA1 is mutated in a large percentage of hereditary breast and ovarian cancers. BRCA1 protein serves as a key enzyme in repairing DNA double-strand breaks. More than 800 mutations in the BRCA1 are clinically significant. This collection of mutations include missense mutations, small deletions, and large rearrangements that result in a protein with reduced function or no protein product. Inheritance of one mutant allele of BRCA1 is associated with 70-80% lifetime risk of developing breast cancer in females. How is this possible? Select all that apply. The loss of the mutant chromosome during mitosis A point mutation in the allele of BRCA1 inherited from the normal parent Repair of the heteroduplex region containing a mismatch between the normal DNA strand and the mutant DNA strand Nondisjunction of the normal chromosome during mitosis A deletion of the gene copy inherited from the affected parent Mitotic recombination in the region between the BRCA1 gene and the…arrow_forward
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