Concept explainers
Marfan syndrome is an autosomal dominant disorder in humans. It results from mutation of the gene on chromosome
Since all cases of Marfan syndrome are caused by mutation of the fibrillin gene, and all family members with Marfan syndrome carry the same mutant allele, how do you e xplain the differences shown in the pedigree?
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- Talk about the challenges involved in determining the genetic components of polygenic illnesses. Explain complementation groups and how the biochemical underpinnings of disease are determined using them. Hereditary illnesses of genomic instability include Werner syndrome, Bloom syndrome, XP, ataxia-telangiectasia, and Fanconi anemia. Which of these ailments has molecular mechanisms behind it? Which kind of genetic instability is connected to which disorder?.arrow_forwardGene mutations can be classified in two major ways:(1) hereditary or germline mutations that are inherited from a parent and are present throughout a person’s life in virtually every cell in the body.(2) acquired or somatic mutations that occur at some time during a person’s life and are present only in certain cells, not in every cell in the body.If there is no family history of a particular disease but a child has the disease then it may have arisen due to a(n) ________ mutation early during development. A) acquired B) inherited C) silent D) transitionarrow_forwardLesch-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.arrow_forward
- Duchenne Muscular Dystrophy (DMD) is a disease that manifests in muscle weakness. It exhibits X-linked recessive inheritance pattern. The dystrophin gene is large and can have many different mutations along the DNA. From the following mutations between the gene sequence (DNA template strand) of a healthy male and an affected brother determine if they would affect the production of mRNA or the sequence of the protein. Base your analysis on the position of the mutation in the transcription unit, and the impact of the change on the codons. Mutation 1: Position -6 Healthy individual A Affected brother C Group of answer choices A. Normal mRNA, normal protein B. No mRNA produced (promoter affected) C. Abnormal mRNA, affected protein D. Normal mRNA, affected protein Base your analysis on the position of the mutation in the transcription unit, and the impact of the change on the codons.arrow_forwardLeber congenital amaurosis (LCA) is a form of congenital blindness in humans and is known to be caused by homozygosity for recessive mutations in the RPE65 gene. Recently, a rare dominant mutation in RPE65 has been implicated as one cause of an eye disease called retinitis pigmentosa, which is characterized by retinal degeneration that can progress to blindness. The dominant RPE65 mutation is a missense mutation causing amino acid 447 in the polypeptide to change from Asp to Glu. Little is known about the nature of the mutant protein. a. Do you think that the dominant allele is more likely a loss-of-function or a gain-of-function mutation? Explain. b. Recently a group of clinicians and scientists reported that gene therapy (gene replacement therapy) for LCA has been at least partially successful. Do you think that the same kind of gene therapy can be used for patients with retinitis pigmentosa caused by the dominant mutant allele of RPE65? Explain.arrow_forwardWhat unusual phenomenon is at work in each of the following disorders?arrow_forward
- Marfan syndrome is due to a mutation in a gene that encodes aprotein called fibrillin-1. It is inherited as a dominant trait. Thefibrillin-1 protein is the main constituent of extracellular microfibrils.These microfibrils can exist as individual fibers or associatewith a protein called elastin to form elastic fibers. People with thedisorder tend to be unusually tall with long limbs, and they mayhave defects in their heart valves and aorta. Let’s suppose aphenotypically unaffected woman has a child with a man whohas Marfan syndrome.A. What is the probability this child will have the disease?B. If this couple has three children, what is the probability thatnone of them will have Marfan syndrome?arrow_forwardIdentify two genetic mechanisms whereby proto-oncogenes can become overexpressed. Select the two mechanisms. Identify two genetic mechanisms whereby proto-oncogenes can become overexpressed.Select the two mechanisms. 1) alterations in chromatin structure 2) a gain-of-function alteration 3)modification of proto-oncogenes products 4)mutations that result in an abnormal protein product 5)mutations within gene-regulatory regionsarrow_forwardTwo missense mutations in the gene that encodes an enzyme called superoxide dismutase cause a form of amyotrophic lateral sclerosis (ALS, or Lou Gehrig disease). This disease causes loss of neurological function over a 5-year period. One mutation alters the amino acid asparagine (Asn) to lysine (Lys). The other changes an isoleucine (Ile) to a threonine (Thr). List the codons involved and describe how single-base mutations can alter the specified amino acids.arrow_forward
- Metabolic syndrome is a genetic disorder with symptoms of hypertension, elevated blood cholesterol concentrations, and lower-than-normal blood magnesium concentrations. This syndrome is caused by a mutation in mitochondrial DNA (mtDNA) in which a thymine nucleotide is replaced by a cytosine nucleotide. Which of the following identifies the mutated mtDNA and the corresponding mRNA and tRNA produced in a person with metabolic syndrome if the normal mtDNA triplet is TCG? Select one: a. Mutated mtDNA: CCG mRNA: GGC tRNA: GGC b. Mutated mtDNA: TCG mRNA: UGC tRNA: ACG c. Mutated mtDNA: CCG mRNA: GGC tRNA: CCG d. Mutated mtDNA: TTG mRNA: AAC tRNA: UUCarrow_forward"Changes to the p53 protein structure can be caused by differences in DNA and can affect protein function." Can you give detailed explanation why this is causation and not correlation? The explanation should be related with mutation, structure changes during protein synthesis, chemical property changes in amino acids, and functions of p53 protein.arrow_forwardWhich of the following are considered to be factors involved in the pathological features of Down Syndrome? Development of beta amyloid plaques Abnormal Superoxide Dismutase activity Hyperphosphorylated Tau proteins Misfolded alpha-synuclein proteins OA & B are correctarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning