Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Chapter 7, Problem 20P
The mutant FMR-1 allele that causes fragile X syndrome is considered to be X-linked dominant with incomplete penetrance and variable expressivity. Why do most females heterozygous for one mutant and one normal allele have at least some symptoms of the disease?
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Chapter 7 Solutions
Genetics: From Genes to Genomes
Ch. 7 - The following is a list of mutational changes. For...Ch. 7 - What explanations can account for the following...Ch. 7 - The DNA sequence of one strand of a gene from...Ch. 7 - Among mammals, measurements of the rate of...Ch. 7 - Over a period of several years, a large hospital...Ch. 7 - Suppose you wanted to study genes controlling the...Ch. 7 - In a genetics lab, Kim and Maria infected a sample...Ch. 7 - The results of the fluctuation test Fig. 7.5 were...Ch. 7 - The following pedigree shows the inheritance of a...Ch. 7 - Autism is a neurological disorder thought to be...
Ch. 7 - Like the yellow Labrador retrievers featured in...Ch. 7 - Remember that Balancer chromosomes prevent the...Ch. 7 - Figure 7.14 shows examples of base substitutions...Ch. 7 - Figure 7.14a shows the mutagen 5-bromouracil 5-BU,...Ch. 7 - So-called two-way mutagens can induce both a...Ch. 7 - In 1967, J. B. Jenkins treated wild-type male...Ch. 7 - When a particular mutagen identified by the Ames...Ch. 7 - Prob. 18PCh. 7 - The Ames test uses the reversion rate His- to His...Ch. 7 - The mutant FMR-1 allele that causes fragile X...Ch. 7 - The physicist Stephen Hawking, famous for his...Ch. 7 - Aflatoxin B1 is a highly mutagenic and...Ch. 7 - In human DNA, 70 of cytosine residues that are...Ch. 7 - Bromodeoxyuridine BrdU is a synthetic nucleoside...Ch. 7 - Albinism in animals is caused by recessive...Ch. 7 - a. In Figure 7.22b, what can you say about the...Ch. 7 - Imagine that you caught a female albino mouse in...Ch. 7 - Plant breeders studying genes influencing leaf...Ch. 7 - In humans, albinism is normally inherited in an...Ch. 7 - a. Seymour Benzers fine structure analysis of the...Ch. 7 - a. You have a test tube containing 5 ml of a...Ch. 7 - Prob. 32PCh. 7 - The rosy ry gene of Drosophila encodes an enzyme...Ch. 7 - Nine rII- mutants of bacteriophage T4 were used in...Ch. 7 - In a haploid yeast strain, eight recessive...Ch. 7 - In Problem 24, you learned that Bloom syndrome is...Ch. 7 - The pathway for arginine biosynthesis in...Ch. 7 - In corn snakes, the wild-type color is brown. One...Ch. 7 - In a certain species of flowering plants with a...Ch. 7 - The intermediates A, B, C, D, E, and F all occur...Ch. 7 - In each of the following cross schemes, two...Ch. 7 - Prob. 42PCh. 7 - The following complementing E. coli mutants were...Ch. 7 - In 1952, an article in the British Medical Journal...Ch. 7 - Mutations in an autosomal gene in humans cause a...Ch. 7 - Antibodies were made that recognize six proteins...Ch. 7 - Prob. 47PCh. 7 - Prob. 48PCh. 7 - In addition to the predominant adult hemoglobin,...Ch. 7 - Most mammals, including New World primates such as...Ch. 7 - Humans are normally trichromats; we have three...
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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
- Normal vision (XA) in humans is dominant to color blindness (Xa) and is X-linked. A man with normal vision, whose father was colorblind, marries a colorblind woman. What are the chances that a son will be colorblind? What are the chances that a daughter will be colorblind? The determiner for brown eyes (B) is dominant to blue eyes (b) and is not X-linked. A colorblind man with brown eyes, whose mother was blue-eyed, marries a blue-eyed woman having normal vision, whose father was colorblind. Show the expected phenotypes ratio of their children involving eye color, color blindness, and sex.arrow_forwardA scientist working with Drosophila flies studies wing length, an X-linked characteristic. He has pure-breeding lines of short-winged and long-winged flies available. He decides to use reciprocal crosses for his work.i) What are reciprocal crosses? ii) Provide an example of the reciprocal crosses this scientist will do.iii) If the gene for wing length was sex-linked, but present in the pseudoautosomal region, what would you expect the outcome of a reciprocal cross to be with regards to males and females?arrow_forwardThe mutant FMR-1 allele that causes fragile X syndrome is considered to be X-linked dominant withincomplete penetrance and variable expressivity.Why do most females heterozygous for one mutantand one normal allele have at least some symptomsof the disease?arrow_forward
- Figure 1-15 shows the family tree, or pedigree, for LouiseBenge (Individual VI-1) who suffers from the diseaseACDC because she has two mutant copies of the CD73gene. She has four siblings (VI-2, VI-3, VI-4, and VI-5)who have this disease for the same reason. Do all of the10 children of Louise and her siblings have the samenumber of mutant copies of the CD73 gene, or mightthis number be different for some of the 10 children?arrow_forwardConsider a couple: a woman who is homozygous for a recessive mutation that causes X-linked colorblindness, and a man with full color vision (he does not carry a copy of the mutation). a) What is the probability that a son of this couple will be colorblind? b) What is the probability that a daughter of the couple will be colorblind?arrow_forwardBarr bodies are formed to adjust X chromosome dosage in species other than humans, such as Drosophila (fruit flies) and C. elegans (nematodes). True or False ?arrow_forward
- y 301 Amelogenesis imperfecta is X-linked dominant. Affected XY individuals have extremely thin enamel on the teeth while XX carriers have grooved teeth from uneven deposition of enamel. If an unaffected XY individual were to produce children with a XX carrier partner, a. what would be the expected chance of a XY child being affected with the disease? b. what would be the expected chance of a XY child being affected with the disease?arrow_forwardMutations in the genes for clotting factor VIII and IX cause hemophilia A and B, respectively. A woman may be heterozygous for mutations in both genes, with a mutated factor VIII allele on one X chromosome, and a mutated factor IX allele on the other. All of her sons should have either hemophilia A or B. However, on rare occasions, one of these women gives birth to a son who does not have hemophilia, and his one X chromosome does not have either mutated allele. Explain.arrow_forwardIn a woman who is a carrier of a mutant OTC deficiency allele, her sons who receive the mutant allele will be affected and her daughters will be carriers who may or may not be symptomatic, depending on random X inactivation in the liver. 1) Is this a single gene inheritance or multifactorial disease? 2) Is there a strong genetic or environmental cause to the development of this disease? If both genetic and environmental causes are implicated, you have to indicate each of them separately.arrow_forward
- In domesticated cats, the following are Independently assorting: 6. Normal ears (T) is dominant to tufted ears (t); Curved whiskers (C) is dominant to straight whiskers (c); The presence of six toes (S) is dominant to five toes (s); Gene for hair length is an X-linked codominant. The three phenotypes for hair length are long (XHXH), medium (X"X*), and short (X"Xh); medium is the heterozygous condition. Given two parents: TtccSSXHXh x TtCcSsXHY a) How many different gametes could be formed in the female cat with respect to these four traits? b) How many different phenotypes are possible in the offspring from this mating?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_forwardDuchenne muscular dystrophy is an X-linked, recessive disorder in which muscles waste away early in life, resulting in death in the teens or twenties. A man and woman in their late thirties have five children—three boys (ages 1, 3, and 10 years) and two girls (ages 5 and 7 years). The oldest, boy shows symptoms of the disease. What are the probabilities that their other children will develop the disease? Give only typing answer with explanation and conclusionarrow_forward
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