ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
6th Edition
ISBN: 9781260406092
Author: HARTWELL, Leland, HOOD, Leroy, Goldberg, Michael
Publisher: Mcgraw-hill Education/stony Brook University
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 13, Problem 25P
Duchenne muscular dystrophy (DMD) is caused by a recessive mutant allele of an X-linked gene called dystrophin. Rarely, females have disease symptoms as severe as those in males hemizygous for the recessive allele. These females are heterozygous for X-autosome reciprocal translocations where the X chromosome breakage occurred in the middle of the dystrophin gene, breaking it into two pieces.
| a. | If it is equally likely for X chromosome inactivation to spread from either of the X chromosome inactivation centers (XICs; see Fig. 12.15) in the cells of this patient, what proportion of her cells would you expect to have normal function of the dystrophin gene? |
| b. | Is it possible that some autosomal genes might be inactivated in some cells of this woman? Is it possible that some X-linked genes that are normally subject to X inactivation might be expressed from both X chromosomes in this woman? To answer these questions, draw a figure showing the normal and translocated chromosomes involved, and the locations of: centromeres, potentially inactivated autosomal genes, X chromosome genes potentially no longer subject to X inactivation, the dystrophin gene, and the XICs. Assume for simplicity that dystrophin and the XIC are located in the middle of the short and long arms of the X chromosome, respectively. |
| c. | It is found that virtually none of the cells in this woman expresses any of the dystrophin gene product. Use your answers to parts (a) and (b) to explain this interesting observation. Consider what changes in gene expression might do to the survival and proliferation of cells. |
| d. | Discuss how scientists might have used X:autosome reciprocal translocations to help map the XIC on the human X chromosome. Why does your answer to part (c) illustrate a potential pitfall of this approach? |
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Amelogenesis imperfecta (AI) is a disorder of faulty tooth enamel formation. It is inherited in an autosomal dominant and X-linked dominant pattern. The expression of AI disorder is determined by mutations in the autosomal alleles. One copy of the mutated allele (A) will cause the disorder. The severity of the disorder is determined by mutations in a gene carried on the X chromosome. Normal (or non-severe) abnormality (XN) is dominant over the abnormality (or severe) (Xn) allele. In the absence of the autosomal dominant allele, the abnormality gene on the X chromosome is not expressed. Question:A woman with normal teeth had four children with a man with non-severe form of AI:
A boy was born without amelogenesis imperfecta
A girl was born without amelogenesis imperfecta
A boy was born with severe amelogenesis imperfecta
A boy was born with non severe amelogenesis imperfecta
Identify the parental genotypes.
Complete the Punnett square for the parental cross, and identify the…
Amelogenesis imperfecta (AI) is a disorder of faulty tooth enamel formation. It is inherited in an autosomal dominant and X-linked dominant pattern. The expression of AI disorder is determined by mutations in the autosomal alleles. One copy of the mutated allele (A) will cause the disorder. The severity of the disorder is determined by mutations in a gene carried on the X chromosome. Normal (or non-severe) abnormality (XN) is dominant over the abnormality (or severe) (Xn) allele. In the absence of the autosomal dominant allele, the abnormality gene on the X chromosome is notexpressed. Question:A woman with normal teeth had four children with a man with non-severe form of AI:
A boy was born without amelogenesis imperfecta
A girl was born without amelogenesis imperfecta
A boy was born with severe amelogenesis imperfecta
A boy was born with non severe amelogenesis imperfecta
Identify the parental genotypes.
Complete the Punnett square for the parental cross, and identify the possible…
Amelogenesis imperfecta (AI) is a disorder of faulty tooth enamel formation. It is inherited in an autosomal dominant and X-linked dominant pattern. The expression of AI disorder is determined by mutations in the autosomal alleles. One copy of the mutated allele (A) will cause the disorder. The severity of the disorder is determined by mutations in a gene carried on the X chromosome. Normal (or non-severe) abnormality (XN) is dominant over the abnormality (or severe) (Xn) allele. In the absence of the autosomal dominant allele, the abnormality gene on the X chromosome is not expressed. Question:A woman with normal teeth had four children with a man with non-severe form of AI:
A boy was born without amelogenesis imperfecta
A girl was born without amelogenesis imperfecta
A boy was born with severe amelogenesis imperfecta
A boy was born with non severe amelogenesis imperfecta
Identify the parental genotypes.
Complete the Punnett square for the parental cross, and identify the…
Chapter 13 Solutions
ND STONY BROOK UNIVERSITY LOOSELEAF GENETICS: FROM GENES TO GENOMES
Ch. 13 - For each of the terms in the left column, choose...Ch. 13 - Prob. 2PCh. 13 - For each of the following types of chromosomal...Ch. 13 - For the following types of chromosomal...Ch. 13 - One of the X chromosomes in a particular...Ch. 13 - A diploid strain of yeast was made by mating a...Ch. 13 - The two graphs that follow represent genomic...Ch. 13 - A series of chromosomal mutations in Drosophila...Ch. 13 - Indicate which of the four major classes of...Ch. 13 - The recessive, X-linked z1 mutation of the...
Ch. 13 - Genes a and b are 21 m.u. apart when mapped in...Ch. 13 - In the following group of figures, the pink lines...Ch. 13 - Three strains of Drosophila Bravo, X-ray, and...Ch. 13 - Two yeast strains were mated and sporulated...Ch. 13 - Suppose a haploid yeast strain carrying two...Ch. 13 - In the mating between two haploid yeast strains...Ch. 13 - During ascus formation in Neurospora, any...Ch. 13 - In the following figure, black and pink lines...Ch. 13 - In Drosophila, the gene for cinnabar eye color is...Ch. 13 - Semisterility in corn, as seen by unfilled ears...Ch. 13 - A promising biological method for insect control...Ch. 13 - Prob. 23PCh. 13 - a. Among the progeny of a self-fertilized...Ch. 13 - Duchenne muscular dystrophy DMD is caused by a...Ch. 13 - WHIM syndrome is a disease of the immune system...Ch. 13 - Explain how transposable elements can cause the...Ch. 13 - The Drosophila genome normally harbors about 40 P...Ch. 13 - Drosophila P elements were discovered because of a...Ch. 13 - Flies homozygous for mutant alleles of a...Ch. 13 - Fred and Mary have a child named Bob. The genomic...Ch. 13 - Uniparental disomy is a rare phenomenon in which...Ch. 13 - Among adults with Turner syndrome, it has been...Ch. 13 - In Neurospora, his2 mutants require the amino acid...Ch. 13 - Human geneticists interested in the effects of...Ch. 13 - The incidence of Down syndrome will be very high...Ch. 13 - The Drosophila chromosome 4 is extremely small;...Ch. 13 - Down syndrome is usually caused by having a...Ch. 13 - Common red clover, Trifolium pratense, is a...Ch. 13 - The numbers of chromosomes in the somatic cells of...Ch. 13 - Prob. 41PCh. 13 - Somatic cells in organisms of a particular diploid...Ch. 13 - An allotetraploid species has a genome composed of...Ch. 13 - Prob. 44PCh. 13 - Chromosomes normally associate during meiosis I as...Ch. 13 - Using whole-genome sequencing, how could you...Ch. 13 - Prob. 47PCh. 13 - Prob. 48PCh. 13 - Seedless watermelons that you find in the...Ch. 13 - The names of hybrid animals are usually themselves...Ch. 13 - While most animals cannot tolerate polyploidy,...Ch. 13 - What characteristic property of translocations...Ch. 13 - Prob. 53PCh. 13 - In the accompanying figure, the top and bottom...Ch. 13 - Prob. 55PCh. 13 - The accompanying figure shows idiograms of human...Ch. 13 - Prob. 57P
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
- X-linked ichthyosis is an X-linked recessive trait that manifests in part as dry, scaly skin (“ichthy-” = fish or fish like). Suppose a couple are considering having a child together. Parent A is heterozygous for the ichthyosis allele while Parent B is hemizygous negative for the ichthyosis allele. What is the probability their child would be unafflicted with ichthyosis but be a carrier of the ichthyosis-causing allele? a.0% b.25% c.50% d.75% e.100%arrow_forwardAchondroplasia 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_forwardConsider a Droscophilia fly with a genotype of Nn XqYY. The dominant allele of the sex-linked gene specifies a black body and the recessive a white body. The recessive autosomal allele specifies hairy bristles while the dominant allele specifies smooth bristles. i)What is the ploidy of this fly? ii) What would the sex of this fly be? iii)What would the phenotype of this fly be with respect to these two loci?arrow_forward
- Anhidrotic ectodermal dysplasia is an X-linked recessive disorder in humans characterized by small teeth, no sweat glands, and sparse body hair. This trait is usually seen in men, but women who are heterozygous carriers of the trait often have irregular patches of skin with few or no sweat glands (see the illustration below). a. Explain why women who are heterozygous carriers of a recessive gene for anhidrotic ectodermal dysplasia have irregular patches of skin lacking sweat glands. b. Why does the distribution of the patches of skin lacking sweat glands differ among the females depicted in the illustration, even between the identical twins?arrow_forwardThe Xg cell-surface antigen is coded for by a gene located on the X chromosome. No equivalent gene exists on the Y chromosome. Two codominant alleles of this gene have been identified: Xg1 and Xg2. A woman of genotype Xg2/Xg2 bears children with a man of genotype Xg1/Y, and they produce a son with Klinefelter syndrome of genotype Xg1/Xg2Y. Using proper genetic terminology, briefly explain how this individual was generated. In which parent and in which meiotic division did the mistake occur?arrow_forwardFaulty Tooth Enamel Formation Amelogenesis imperfecta (AI) is a disorder of faulty tooth enamel formation. It is inherited in an autosomal dominant and X-linked dominant pattern. The expression of AI disorder is determined by mutations in the autosomal alleles. One copy of the mutated allele (A) will cause the disorder. The severity of the disorder is determined by mutations in a gene carried on the X chromosome. Normal (or non-severe) abnormality (XN) is dominant over the abnormality (or severe) (Xn) allele. In the absence of the autosomal dominant allele, the abnormality gene on the X chromosome is notexpressed. Question:A woman with normal teeth had four children with a man with non-severe form of AI: A boy was born without amelogenesis imperfecta A girl was born without amelogenesis imperfecta A boy was born with severe amelogenesis imperfecta A boy was born with non severe amelogenesis imperfecta Identify the parental genotypes. Complete the Punnett square for the parental…arrow_forward
- Hemophilia is another example of a X-linked disease caused when a recessive allele (Xh) is expressed. If a normal male reproduces with a heterozygous normal female, what are the expected genotypes and phenotypes? Will any of their daughters develop hemophilia? As in the previous question, you must also give the gender of the child in your genotype and phenotype descriptions here.arrow_forwardHemophilia is another example of an X-linked disease caused when a recessive allele (Xh) is expressed. If a normal male reproduces with a heterozygous normal female, what are the expected genotypes and phenotypes? Will any of their daughters develop hemophilia?arrow_forwardLet’s suppose that two different X-linked genes exist in mice,designated with the letters N and L. Gene N exists in a dominant,normal allele and in a recessive allele, n, that is lethal. Similarly,gene L exists in a dominant, normal allele and in a recessive allele,l, that is lethal. Heterozygous females are normal, but males thatcarry either recessive allele are born dead. Explain whether or notit would be possible to map the distance between these two genesby making crosses and analyzing the number of living and deadoffspring. You may assume that you have strains of mice in whichfemales are heterozygous for one or both genes.arrow_forward
- Familial Down syndrome is similar to primary Down syndrome in that it is caused by trisomy 21. However, in familial Down syndrome, all or part of the third copy of chromosome 21 has translocated onto another autosome, typically chromosome 14. In cases of familial Down syndrome, one of the parents of the affected child is often a carrier of a translocated chromosome. The translocation carrier parent does not have Down syndrome because he or she has a total of two copies of chromosome 21. Suppose that a woman is a translocation carrier of chromosome 21 on chromosome 14. She conceives six zygotes with a man who carries no aneuploidies. Match the description of the chromosomes inherited by each zygote with the viability and phenotype of the zygote. ✓ Two normal copies of 14, two normal copies of 21 two normal copies of 21, one normal copy of 14 ✓one normal copy of 14, one 21 to 14 translocation, one normal copy of 21 ✓two normal copies of 14, one normal copy of 21, on 21 to 14…arrow_forwardRetinoblastoma can be seen as a familial cancer, inherited in an autosomal recessive manner (RB-/RB-), individuals heterozygous for the RB+ and RB- alleles can develop tumor as a result of… A mitotic crossover that leads to homozygosity for RB+ in some cells and RB- in other cells A meiotic mutation in the RB+ allele that leads to homozygosity for RB+ A somatic mutation in the RB- allele that leads to homozygosity for RB+ The fact that RB- is dominant to RB+arrow_forwardIn Drosophila, the white gene located on the X chromosome affects eye color; an autosomal gene, wingless, is on an autosomal chromosome. Use the following allele symbols: Xw+ _ , Xw+Y = wild type red eyes; X-linked dominant allele Xw Xw , XwY = white eyes; X-linked recessive allele Y = Y sex chromosome vg+ = wild type wings; autosomal dominant vg = wingless; autosomal recessive Predict ratios/proportions of genotypes and phenotypes of offspring from the following cross, of a white-eyed male with wild type wings and a wild type red eyed female with wild type wings: indicate sex of offspring along with phenotypes. XwY vg+ vg x Xw+Xw vg+vgarrow_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 Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning
Biology Today and Tomorrow without Physiology (Mi...BiologyISBN:9781305117396Author:Cecie Starr, Christine Evers, Lisa StarrPublisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
Human Biology (MindTap Course List)
Biology
ISBN:9781305112100
Author:Cecie Starr, Beverly McMillan
Publisher:Cengage Learning
Biology Today and Tomorrow without Physiology (Mi...
Biology
ISBN:9781305117396
Author:Cecie Starr, Christine Evers, Lisa Starr
Publisher:Cengage Learning
Mitochondrial mutations; Author: Useful Genetics;https://www.youtube.com/watch?v=GvgXe-3RJeU;License: CC-BY