Genetics: From Genes to Genomes, 5th edition
5th Edition
ISBN: 9780073525310
Author: Leland H. Hartwell, Michael L. Goldberg, Janice A. Fischer, Leroy Hood, Charles F. Aquadro
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 20, Problem 26P
In Europe, the frequency of the CF allele causing the recessive autosomal disease cystic fibrosis is about 0.04. Cystic fibrosis causes death before reproduction in virtually all cases.
| a. | Determine values of relative fitness (W) for the unaffected, carrier, and affected genotypes. Assume that no selective advantage is associated with heterozygosity for the disease allele. |
| b. | Given your answer to part (a), determine the average (mean) fitness at birth of the population as a whole with respect to the cystic fibrosis trait (
|
| c. | Suppose the European population is at equilibrium for the frequency of the CF- allele because some heterozygote advantage exists. Recalculate the relative fitness values for the three genotypes under this assumption |
| d. | The CFTR protein encoded by the CF gene is a chloride ion channel. People suffering from cholera have diarrhea that pumps water and chloride ions out of the small intestine. Use these facts to explain why a heterozygote advantage might in fact exist for the CF gene |
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Cystic fibrosis (CF) is a recessive autosomal disorder. In certainpopulations of Northern European descent, the number of peopleborn with this disorder is about 1 in 2500. Assuming Hardy-Weinberg equilibrium for this trait:A. What are the frequencies for the common (non-disease-causing)allele and the mutant (disease-causing) allele.B. What are the genotype frequencies of homozygous unaffected,heterozygous, and homozygous affected individuals?C. Assuming random mating, what is the probability that twophenotypically unaffected heterozygous carriers will chooseeach other as mates?
. In Europe, the frequency of the CF− allele causing therecessive autosomal disease cystic fibrosis is about0.04. Cystic fibrosis causes death before reproductionin virtually all cases.a. Determine values of relative fitness (W) for the unaffected, carrier, and affected genotypes. Assumethat no selective advantage is associated with heterozygosity for the disease allele.b. Given your answer to part (a), determine the average (mean) fitness at birth of the population as awhole with respect to the cystic fibrosis trait (W)and the expected change in allele frequency overone generation (Δq) when measured at the birth ofthe next generation.c. Suppose the European population is at equilibriumfor the frequency of the CF− allele because someheterozygote advantage exists. Recalculate the relative fitness values for the three genotypes underthis assumption. d. The CFTR protein encoded by the CF gene is achloride ion channel. People suffering from cholerahave diarrhea that pumps water and…
Identify each of the following as an example of allele, genotype, and/or phenotype frequency:
A. Approximately 1 in 2500 people of Northern European descent is born with cystic fibrosis.
B. The percentage of carriers of the sickle cell allele in West Africa is approximately 13%.
C. The number of new mutations for achondroplasia, a genetic disorder, is approximately 5 × 10–5.
Chapter 20 Solutions
Genetics: From Genes to Genomes, 5th edition
Ch. 20 - Choose the best matching phrase in the right...Ch. 20 - When an allele is dominant, why does it not always...Ch. 20 - A population with an allele frequency p of 0.5 and...Ch. 20 - Prob. 4PCh. 20 - Which of the following populations are at...Ch. 20 - A dominant mutation in Drosophila called Delta...Ch. 20 - A large, random mating population is started with...Ch. 20 - Prob. 8PCh. 20 - Prob. 9PCh. 20 - Two hypothetical lizard populations found on...
Ch. 20 - It is the year 1998, and the men and women sailors...Ch. 20 - Prob. 12PCh. 20 - In 1927, the ophthalmologist George Waaler tested...Ch. 20 - Prob. 14PCh. 20 - A gene has two alleles A frequency = p and a...Ch. 20 - Some people can taste the bitter compound...Ch. 20 - Androgenetic alopecia pattern baldness is a...Ch. 20 - Why is the elimination of a fully recessive...Ch. 20 - Tristan da Cunha is a group of small islands in...Ch. 20 - Small population size causes genetic drift because...Ch. 20 - Prob. 21PCh. 20 - A mouse mutation with incomplete dominance t =...Ch. 20 - In Drosophila, the vestigial wings recessive...Ch. 20 - Prob. 24PCh. 20 - You have identified an autosomal gene that...Ch. 20 - In Europe, the frequency of the CF allele causing...Ch. 20 - An allele of the G6PD gene acts in a recessive...Ch. 20 - Explain why evolutionary biologists monitor...Ch. 20 - What is the most straightforward evidence at the...Ch. 20 - In March 2013, the American Journal of Human...Ch. 20 - If you go back 40 generations into your biological...Ch. 20 - In Fig. 21.17, to what part of the world does...Ch. 20 - Predict the DNA sequences at the four nodes...Ch. 20 - A cladogram not drawn to scale for the taxonomic...Ch. 20 - As noted in Fig. 21.22, humans now living in...
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
- Excessive secretion of male sex hormones results in premature sexual maturation in males and masculization of the sex characters in females. This disorder is called the adrenogenital syndrome, and in Switzerland there is an autosomal recessive form of the disease that affects about one in 5000 newborns. a. Assuming random mating, what is the allele frequency of the recessive? b. What is the frequency of heterozygous carriers?arrow_forwardIdentify each of the following as an example of allele, genotype,and/or phenotype frequency:A. Approximately 1 in 2500 individuals of Northern Europeandescent is born with cystic fibrosis.B. The percentage of carriers of the sickle cell allele in WestAfrica is approximately 13%.C. The number of new mutations per generation resultingin achondroplasia, a genetic disorder, is approximately5 × 10−5.arrow_forwardCystic fibrosis (CF) is a recessive autosomal disorder. In certain populations of Northern European descent, the number of people born with this disorder is about 1 in 2500. Assuming Hardy- Weinberg equilibrium for this trait: A. What are the frequencies for the normal and CF alleles? B. What are the genotype frequencies of homozygous normal, heterozygous, and homozygous affected individuals? C. Assuming random mating, what is the probability that two phenotypically unaffected heterozygous carriers will choose each other as mates?arrow_forward
- a. Alleles of genes on the X chromosome can also be atequilibrium, but the equilibrium frequencies underthe Hardy-Weinberg assumptions must be calculatedseparately for the two sexes. For a gene with two alleles A and a at frequencies of p and q, respectively,write expressions that describe the equilibrium frequencies for all the genotypes in men and women.b. Approximately 1 in 10,000 males in the UnitedStates is afflicted with hemophilia, an X-linkedrecessive condition. If you assume that the population is at Hardy-Weinberg equilibrium, what proportion of American females would be hemophiliacs?About how many female hemophiliacs would youexpect to find among the 170 million women livingin the United States? (Assume that all females withhemophilia are homozygous for the disease allele.)arrow_forwardIn humans, the genetic disease cystic fibrosis is caused by a recessive allele (a). The normal (healthy) allele is dominant (A). What is the genotype of someone who has cystic fibrosis? What are the two different genotypes that a healthy person could have? If two people were both heterozygous for the cystic fibrosis gene, what fraction of their children would be likely to have this disease? Hint: Draw a Punnett square to figure it out.arrow_forwardConsider the case of a hypothetical genetic disease called WhySciEleven (WSE), an inherited disease that results to the inability to complete production of an amino acid “moduleactivity” that results in brain damage if untreated. WSE is due to a recessive allele. Given one WSE occurrence per 10,000 births. 1. What is the frequency of the dominant allele? 2. What is the frequency of the recessive allele for WSE in population? 3. What is the frequency of the heterozygous people?arrow_forward
- The chart below is showing 4 generations of a family that is affected by a hereditary disease. a. Is the disorder being tracked dominant or recessive? How do you know? b. There is only one possible genotype for person C. True or False? c. What are the possible genotypes for person A? d. What are the possible genotypes for person B?, e. If two people with the same genotypes as person C's spouse and person A's spouse had a child, what is the probability that the child will be affected by this genetic disorder? (draw a Punnett square using the correct genotypes to help you). % chance offspring will be affected % chance offspring will not be affectedarrow_forwardOne particularly useful feature of the Hardy-Weinberg equation is that it allows us to estimate the frequency of heterozygotes for recessive genetic diseases, assuming that Hardy-Weinberg equilibrium exists. As an example, let’s consider cystic fibrosis, which is a human genetic disease involving a gene that encodes a chloride transporter. Persons with this disorder have an irregularity in salt and water balance. One of the symptoms is thick mucus in the lungs that can contribute to repeated lung infections. In populations of Northern European descent, the frequency of affected individuals is approximately 1 in 2500. Because this is a recessive disorder, affected individuals are homozygotes. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of individuals who are heterozygous carriers?arrow_forwardA mutant allele in persons with familial hypercholesterolemia (FH) causes death due to a lack of liver receptors for LDL. Susceptible persons have half the normal number of receptors, while other individuals have the normal number of receptors. In a phenotypically normal couple, the man had a female 1 cousin (on his father’s side) who died from FH; the woman had a maternal uncle with FH. a. Calculate the probability that neither of the couple might be susceptible. b. Calculate the probability that one of them might be susceptible, but the other is not. c. Calculate the probability that they will have an FH child if a test discloses that both of them are susceptible.arrow_forward
- Consider the following scenario: A man without freckles (freckles are a dominant trait, determined by the dominant allele “F”) is a carrier of cystic fibrosis (recall that CF is a recessive trait, determined by the recessive allele "a"), mates with a woman whose genotype is heterozygous for freckles and is also a carrier of CF. Assume the two genes in question are in different chromosomes and, therefore, assort independently. Complete the following Punnett square to generate the offspring probabilities from this couple, by entering the genotypes of the parents, the gametes, and the offspring for the two traits described above. (4) Father’s genotype ffAa Mother’s genotypeFfAa ● Sperm: fA ● Sperm: fa ● Sperm: fA ● Sperm: fa ● Egg: FA ● Egg: fA ● Egg: Fa ● Egg: fa What is the probability for this couple to have a child with freckles? What is the…arrow_forwardFor each of the following characteristics, indicate whether it would be considered a discontinuous characteristic or a quantitative characteristic. Briefly justify your answer. a. Kernel color in a strain of wheat, in which two codominant alleles segregating at a single locus determine the color. Thus, there are three phenotypes present in this strain: white, light red, and medium red. b. Body weight in a family of Labrador retrievers. An autosomal recessive allele that causes dwarfism is present in this family. Two phenotypes are recognized: dwarf (less than 13 kg) and normal (greater than 23 kg). c. Presence or absence of leprosy. Susceptibility to leprosy is determined by multiple genes and numerous environmental factors. d. Number of toes in guinea pigs, which is influenced by genes at many loci. e. Number of fingers in humans. Extra (more than five) fingers are caused by the presence of an autosomal dominant allele.arrow_forwardAn autosomal locus has alleles A and a. We are given the frequency of individuals with the autosomal recessive phenotype. Which of the following statements is TRUE? Choose all that are true. Note: HWE = Hardy-Weinberg equilibrium a) If we assume HWE, we can calculate both allele frequencies b) If we assume HWE, we can calculate the genotype frequencies that we weren't given c) We can calculate both allele frequencies even if we don't assume HWE d) We can calculate q = Freq(a) even if we don't assume HWE e) Even if we don't assume HWE, we can calculate the genotype frequencies that we weren't givenarrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSON
Biology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax
Anatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:9780815344322
Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education
Mendelian Genetics and Punnett Squares; Author: Professor Dave Explains;https://www.youtube.com/watch?v=3f_eisNPpnc;License: Standard YouTube License, CC-BY
The Evolution of Populations: Natural Selection, Genetic Drift, and Gene Flow; Author: Professor Dave Explains;https://www.youtube.com/watch?v=SRWXEMlI0_U;License: Standard YouTube License, CC-BY