EBK GENETICS: FROM GENES TO GENOMES
6th Edition
ISBN: 9781260041255
Author: HARTWELL
Publisher: MCGRAW HILL BOOK COMPANY
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 11, Problem 41P
Table 11.2 and Fig. 11.27 together portray the search for the mutation causing Nic Volker’s severe inflammatory bowel disease. Neither of Nic’s parents had the condition, so geneticists narrowed their investigation by focusing on rare variants that showed a recessive pattern and those on the X chromosome.
| a. | For candidate variants on an autosome, would the researchers have looked only for variants for which Nic is homozygous? Explain. |
| b. | Apart from the recessive and X-linked hypotheses, do any other possible explanations exist for Nic’s condition? |
| c. | The causative mutation was pinpointed by analyzing only Nic’s exome, because at the time of these investigations, whole-genome or whole-exome sequencing was too expensive to perform on his parents. How could you determine inexpensively whether or not this mutation occurred de novo in the germ line of one of his parents (that is, during the formation of the particular egg or sperm that produced Nic)? Your answer should not involve whole-genome or whole-exome sequencing. |
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Susan’s grandfather was deaf, and passed down a hereditary form of deafness within Susan’s family as shown in Figure Q19–12.A. Is this mutation most likely to be dominant or recessive?B. Is it carried on an autosome or a sex chromosome? Why?C. A complete SNP analysis has been done for all of the 11 grandchildren (4 affected, and 7 unaffected). In comparing these 11 SNP results, how long a haplotype block would you expect to find around the critical gene? How might you detect it?
Two related forms of muscular dystrophy—Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD)—are both recessive, X-linked, single-gene conditions caused by point mutations, deletions, and insertion in the dystrophin gene. Each mutated form of dystrophin is one allele. Of the two diseases, DMD is much more severe. Given your knowledge of mutations, the genetic code, and translation, propose an explanation for why the two disorders differ greatly in severity.
Consider two hypothetical recessive autosomal genes a and b, where a heterozygote is testcrossed to a double- homozygous mutant. Predict the phenotypic ratios under the following conditions: (a) a and b are located on separate autosomes. (b) a and b are linked on the same autosome but are so far apart that a crossover always occurs between them. (c) a and b are linked on the same autosome but are so close together that a crossover almost never occurs.
Chapter 11 Solutions
EBK GENETICS: FROM GENES TO GENOMES
Ch. 11 - Choose the phrase from the right column that best...Ch. 11 - Would you characterize the pattern of inheritance...Ch. 11 - Would you be more likely to find single nucleotide...Ch. 11 - A recent estimate of the rate of base...Ch. 11 - If you examine Fig. 11.5 closely, you will note...Ch. 11 - Approximately 50 million SNPs have thus far been...Ch. 11 - Mutations at simple sequence repeat SSR loci occur...Ch. 11 - Humans and gorillas last shared a common ancestor...Ch. 11 - In 2015, an international team of scientists...Ch. 11 - Using PCR, you want to amplify an approximately 1...
Ch. 11 - Prob. 11PCh. 11 - The previous problem raises several interesting...Ch. 11 - You want to make a recombinant DNA in which a PCR...Ch. 11 - You sequence a PCR product amplified from a...Ch. 11 - Prob. 15PCh. 11 - The trinucleotide repeat region of the Huntington...Ch. 11 - Sperm samples were taken from two men just...Ch. 11 - Prob. 18PCh. 11 - a. It is possible to perform DNA fingerprinting...Ch. 11 - On July 17, 1918, Tsar Nicholas II; his wife the...Ch. 11 - The figure that follows shows DNA fingerprint...Ch. 11 - Microarrays were used to determine the genotypes...Ch. 11 - A partial sequence of the wild-type HbA allele is...Ch. 11 - a. In Fig. 11.17b, PCR is performed to amplify...Ch. 11 - The following figure shows a partial microarray...Ch. 11 - Scientists were surprised to discover recently...Ch. 11 - The microarray shown in Problem 25 analyzes...Ch. 11 - The figure that follows shows the pedigree of a...Ch. 11 - One of the difficulties faced by human geneticists...Ch. 11 - Now consider a mating between consanguineous...Ch. 11 - The pedigree shown in Fig. 11.22 was crucial to...Ch. 11 - You have identified a SNP marker that in one large...Ch. 11 - The pedigrees indicated here were obtained with...Ch. 11 - Approximately 3 of the population carries a mutant...Ch. 11 - The drug ivacaftor has recently been developed to...Ch. 11 - In the high-throughput DNA sequencing protocol...Ch. 11 - A researcher sequences the whole exome of a...Ch. 11 - As explained in the text, the cause of many...Ch. 11 - Figure 11.26 portrayed the analysis of Miller...Ch. 11 - A research paper published in the summer of 2012...Ch. 11 - Table 11.2 and Fig. 11.27 together portray the...Ch. 11 - The human RefSeq of the entire first exon of a...Ch. 11 - Mutations in the HPRT1 gene in humans result in at...Ch. 11 - Prob. 44P
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- In 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_forwardThe wild-type (normal) fruit fly, Drosophila melanogaster, has straight wings and long bristles. Mutant strains have been isolated with either curled wings or short bristles. The genes representing these two mutant traits are located on separate chromosomes. Carefully examine the data from the five crosses below. (a) For each mutation, determine whether it is dominant or recessive. In each case, identify which crosses support your answer; and (b) define gene symbols and determine the genotypes of the parents for each cross. Cross 1. straight, short X straight, short 2. straight, long X straight, long 3. curled, long X straight, short 4. straight, short X straight, short 5. curled, short X straight, short straight wings, long bristles 30 120 40 40 20 Number of Progeny straight curled wings, wings, short long bristles bristles 90 10 0 40 120 60 40 40 0 20 curled wings, short bristles 30 0 40 0 60arrow_forwardThe wild-type (normal) fruit fly, Drosophila melanogaster, has straight wings and long bristles. Mutant strains have been isolated with either curled wings or short bristles. The genes representing these two mutant traits are located on separate chromosomes. Carefully examine the data from the five crosses below. (a) For each mutation, determine whether it is dominant or recessive. In each case, identify which crosses support your answer; and (b) define gene symbols and determine the genotypes of the parents for each cross.arrow_forward
- Leber Congenital Amaurosis (LCA) causes progressive vision loss due to defects in the gene that encodes RPE65 isomerase. Affected individuals are homozygous recessive for mutant alleles of the RPE65 gene. You are trying to determine the molecular nature of the mutations in three individuals with LCA. For ease of analysis, you may assume that each individual is homozygous for the same mutant allele (though the three individuals have different mutations than each other). You use the polymerase chain reaction to amplify DNA from each patient and you determine the sequence of the DNA and compare it to unaffected individuals. You identify the following differences. Note that the non-template strand of DNA is given and the changes are highlighted using red boldface. You can assume that the sequences are in the first reading frame (eg. the first three nucleotides of each sequence is a codon). The coding region of the gene is 1602 bp and the position of the sequences shown below is…arrow_forwardWhite eyes in Drosophila melanogaster result from an X-linked recessive mutation. Occasionally, white-eyed mutants give rise to offspring that possess white eyes with small red spots. The number, distribution, and size of the red spots are variable. Explain how a transposable element could be responsible for this spotting phenomenon.arrow_forwardMutations in the HPRT1 gene in humans result in atleast two clinical syndromes. Consult OMIM (www.omim.org) by querying HPRT1; you will only needto look briefly at the top three hits (files #300322,300323, and 308000).a. What is the full name of the HPRT1 enzyme?b. On which chromosome is the HPRT1 gene located?c. Mutations in HPRT1 are associated with two different syndromes. What are these syndromes? Foreach, answer the following questions: (i) What arethe symptoms associated with the syndrome? (ii) Isthe mutant allele that causes the syndrome dominant, recessive, codominant, or incompletely dominant with respect to the normal allele, or do specialconditions apply? (iii) Is the syndrome associatedwith a loss-of-function or a gain-of-function disease allele? (iv) Does the syndrome display allelicheterogeneity? (v) Does the syndrome display locus heterogeneity? (Note: You do not need to understand everything in the OMIM entries to answerthese questions.)arrow_forward
- Duchenne 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_forwardTamryn has a son who has Duchenne muscular dystrophy, which is inherited as an X-linked recessive trait. At a molecular level, the disease is due to lack of the protein dystrophin. Tamryn participates in a study to look at dystrophin levels in various muscles, so has cells sampled from 10 different muscles. Some cells make dystrophin, and some do not. An explanation for this finding is that the mutation is only present in some muscle cells. Tamryn is making less dystrophin as she gets older. The study should be repeated at different ages. Tamryn does not have a Y chromosome the X chromosome that bears the mutation is turned on in some cells but inactivated in others O the mutation originated in the sonarrow_forwardWith the understanding of DNA methylation and gene expression, answer these following questions with as little word as possible. a. What is the difference between a CpG Island vs a CpG-poor region of the genome? b. What is the typical effect of 5mCpG on gene expression, and what two classes of DNA sequences are most heavily methylated? c. What is sex-specific genomic imprinting? Cite at least one example with the given example. d. What is the main function of HOX genes: specifically, the ANT-C vs. the BX-C clusters?arrow_forward
- Our understanding of maternal effect genes has been greatly aided by their identification in experimental organisms such as Drosophila melanogaster and Caenorhabditis elegans. In experimental organisms with a short generation time, geneticists have successfully searched for mutant alleles that prevent the normal process of embryonic development. In many cases, the offspring die at early embryonic or larval stages. These are called maternal effect lethal alleles. How would a researcher identify a mutation that produced a recessive maternal effect lethal allele?arrow_forwardThe Drosophila gene Sex lethal (Sxl) is deserving of itsname. Certain alleles have no effect on XY animals butcause XX animals to die early in development. Other alleles have no effect on XX animals but cause XY animals to die early in development. Thus, some Sxl allelesare lethal to females, while others are lethal to males.a. Would you expect a null mutation in Sxl to causelethality in males or in females? b. Why do Sxl alleles of either type cause lethality ina specific sex?The gene transformer (tra) gets its name from sexualtransformation, as some tra alleles can change XXanimals into morphological males, while other traalleles can change XY animals into morphologicalfemales.c. Which of these sex transformations would becaused by null alleles of tra and which would becaused by constitutively active alleles of tra?d. In contrast with Sxl, null tra mutations do notcause lethality either in XX or in XY animals.However, the Sxl protein regulates the productionof the Tra protein. Why…arrow_forwardA. Deletion of the SOX9 gene leads to sex reversal resulting in a person with karyotype 46XY being phenotypically Explain the genetic basis for this. B. Describe what would happen to the phenotype of a male with a mutation in the gene encoding SF1? Explain your answer.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
Mitochondrial mutations; Author: Useful Genetics;https://www.youtube.com/watch?v=GvgXe-3RJeU;License: CC-BY