Genetic Analysis: An Integrated Approach (3rd Edition)
3rd Edition
ISBN: 9780134605173
Author: Mark F. Sanders, John L. Bowman
Publisher: PEARSON
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Chapter 20, Problem 19P
Sickle cell disease (SCD) is found in numerous populations whose ancestral homes are in the malaria belt of Africa and Asia. SCD is an autosomal recessive disorder that results from homozygosity for a mutant
a. What are the frequencies of the wild
b. What is the frequency of carriers of SCD in the population?
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The prevalence (frequency) of sickle-cell disease in Canada is quite low, affecting 1/3800 individuals. However, in some African populations 1/25 individuals are affected by sickle-cell disease. The difference in frequency of this allele within the differing populations has to do with the adaptation pressures that exist in the different environments. Individuals with the heterozygous genotype have a survival advantage in environments where the disease malaria is prevalent as the presence of this mutant allele leads to resistance to malaria. Therefore, the sickle-cell disease tends to be more frequent in environments where the malaria parasite is most common.
Question:
Explain why the sickle-cell disease remains frequent in some populations while it exists in very low frequency in other populations.
What would happen to the frequency of heterozygous carriers of sickle-cell anemia (with AS genotype) if mosquitoes were completely wiped out in a large region?
In a randomly mating population of mice, 3 out of 200 mice are anemic. Anemia is a recessive condition where the affected mice do not have enough red blood cells to carry the required oxygen molecules to the tissues.
What is the expected frequency of the homozygous dominant genotype for anemia in this population?
Chapter 20 Solutions
Genetic Analysis: An Integrated Approach (3rd Edition)
Ch. 20 - 20.1 Compare and contrast the terms in each of the...Ch. 20 - In a population, what is the consequence of...Ch. 20 - 20.3 Identify and describe the evolutionary forces...Ch. 20 - Describe how natural selection can produce...Ch. 20 - Thinking creatively about evolutionary mechanisms,...Ch. 20 - 20.6 Genetic drift, an evolutionary process...Ch. 20 - Over the course of many generations in a small...Ch. 20 - Catastrophic events such as loss of habitat,...Ch. 20 - 20.9 George Udny Yule was wrong in suggesting that...Ch. 20 - 20.10 The ability to taste the bitter compound...
Ch. 20 - Figure 20.6 illustrates the effect of an ethanol ...Ch. 20 - 20.12 Biologists have proposed that the use of...Ch. 20 - 20.13 Two populations of deer, one of them large...Ch. 20 - 20.14 Directional selection presents an apparent...Ch. 20 - 20.15 What is inbreeding depression? Why is...Ch. 20 - 20.16 Certain animal species, such as the...Ch. 20 - Genetic Analysis 20.1 predicts the number of...Ch. 20 - 20.18 In a population of rabbits, and . The...Ch. 20 - Sickle cell disease (SCD) is found in numerous...Ch. 20 - 20.20 Epidemiologic data on the population in the...Ch. 20 - The frequency of tasters and nontasters of PTC...Ch. 20 - Tay-Sachs disease is an autosomal recessive...Ch. 20 - 20.23 Cystic fibrosis (CF) is the most common...Ch. 20 - 20.24 In the mouse, Mus musculus, survival in...Ch. 20 - 20.25 In a population of flowers growing in a...Ch. 20 - Assume that the flower population described in the...Ch. 20 - 20.27 ABO blood type is examined in a Taiwanese...Ch. 20 - 20.28 A total ofmembers of a Central American...Ch. 20 - 20.29 A sample offield mice contains individuals...Ch. 20 - Prob. 30PCh. 20 - Albinism, an autosomal recessive trait...Ch. 20 - 20.32 The frequency of an autosomal recessive...Ch. 20 - 20.33 Evaluate the following pedigree, and answer...Ch. 20 - Evaluate the following pedigree, and answer the...Ch. 20 - The following is a partial pedigree of the British...Ch. 20 - Draw a separate hypothetical pedigree identifying...Ch. 20 - Prob. 37PCh. 20 - 20.38 Achromatopsia is a rare autosomal recessive...Ch. 20 - 20.39 New allopolyploid plant species can arise by...
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- A total of 1000 members of a Central American population are typed for the ABO blood group. In the sample, 421 have blood type A, 168 have blood type B, 336 have blood type O, and 75 have blood type AB. Part A Use this information to determine the frequency of ABO blood group alleles in the sample. Recall that when considering genes with three alleles whose frequencies are represented by the variables p, q, and r, the sum of genotype frequencies resulting from trinomial expansion is: (p+q+r)² =p² + 2pq+q2+2pr+r²+2gr = 1arrow_forward8% of XY individuals are color blind in a population. Assume Hardy-Weinberg conditions. Submit your answer as it is. a) What is the percentage of color-blind XX individuals? b) What is the percentage of XX individuals who are carriers? c) If this population has 1000 individuals with 50% of male and 50% of female, how many carriers are present in this population? Submit your answer as it is. Do not round up.arrow_forwardThe allele of the gene responsible for the lung disorder, cystic fibrosis rose to prominence in Europe in the 1800s. Cystic fibrosis disease results from thick mucus accumulating in the lungs, which occurs in individuals who are homozygous for the CF allele. A pleiotropic effect is that heterozygous individuals are less likely to suffer from diarrhea. During the European cholera epidemics of the 1800s, resistance against diarrhea conferred a survival advantage such that approximately one in every 400 people in some European populations have cystic fibrosis. Fill in the table below with the genotype and allele frequencies for this 1 in 400 occurrence and provide the Hardy-Weinberg principle model you will be using. (Assume that individuals with the cystic fibrosis trait (CF) reproduce normally and that good sanitation means that there is currently no fitness advantage to diarrhea resistance.) phenotype CF DR normal (totals) Genotype cc Cc CC Number of Individuals 1 ______…arrow_forward
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