Essentials of Genetics (9th Edition) - Standalone book
9th Edition
ISBN: 9780134047799
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino
Publisher: PEARSON
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Chapter 22, Problem 23PDQ
In a recent study of cichlid fish inhabiting Lake Victoria in Africa, Nagl et al. (1998. Proc. Natl. Acad. Sci. [USA] 95: 14,238–14,243) examined suspected neutral sequence polymorphisms in noncoding genomic loci in 12 species and their putative river-living ancestors. At all loci, the same polymorphism was found in nearly all of the tested species from Lake Victoria, both lacustrine and riverine. Different polymorphisms at these loci were found in cichlids at other African lakes.
(a) Why would you suspect neutral sequences to be located in noncoding genomic regions?
(b) What conclusions can be drawn from these polymorphism data in terms of cichlid ancestry in these lakes?
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In a study of a muscle disorder, several affected families exhibited vision problems, muscle weakness, and deafness (M. Zeviani et al. 1990. American Journal of Human Genetics 47:904–914). Analysis of the mtDNA from affected members of these families revealed that large numbers of their mtDNA molecules possessed deletions of varying lengths. Different members of the same family and even different mitochondria from the same person possessed deletions of different sizes, so the underlying defect appeared to be a tendency for the mtDNA of affected persons to have deletions. A pedigree of one of the families studied is shown below. The researchers concluded that this disorder is inherited as an autosomal dominant trait, and they mapped the diseasecausing gene to a position on chromosome 10 in the nucleus.
Q. What characteristics of the pedigree rule out inheritance of a trait encoded by a gene in the mtDNA as the cause of this disorder?
In a study of a muscle disorder, several affected families exhibited vision problems, muscle weakness, and deafness (M. Zeviani et al. 1990. American Journal of Human Genetics 47:904–914). Analysis of the mtDNA from affected members of these families revealed that large numbers of their mtDNA molecules possessed deletions of varying lengths. Different members of the same family and even different mitochondria from the same person possessed deletions of different sizes, so the underlying defect appeared to be a tendency for the mtDNA of affected persons to have deletions. A pedigree of one of the families studied is shown below. The researchers concluded that this disorder is inherited as an autosomal dominant trait, and they mapped the diseasecausing gene to a position on chromosome 10 in the nucleus.
Q. Explain how a mutation in a nuclear gene might lead to deletions in mtDNA.
For three years, Gunther Schlager and Margaret Dickie estimated theforward and reverse mutation rates for five loci in mice that encodevarious aspects of coat color by examining more than 5 million mice forspontaneous mutations (G. Schlager and M. M. Dickie. 1966. Science151:205–206). They detected the following numbers of mutations at thedilute locus:
Gametes examined Mutations detectedForwardmutations 260,675 5Reversemutations 583,360 2
Calculate the forward and reverse mutation rates at this locus. If thesemutations rates are representative of rates in natural populations of mice,what would the expected equilibrium frequency of dilute mutations be?
Chapter 22 Solutions
Essentials of Genetics (9th Edition) - Standalone book
Ch. 22 - CASE STUDY |An unexpected outcome A newborn...Ch. 22 - CASE STUDY |Anunexpected outcome A newborn...Ch. 22 - CASE STUDY|An unexpected outcome A newborn...Ch. 22 - HOW DO WE KNOW? Population geneticists study...Ch. 22 - Review the Chapter Concepts on page 441. All these...Ch. 22 -
3. Price et al. (1999. J. Bacteriol. 181:...Ch. 22 -
4. The genetic difference between two Drosophila...Ch. 22 - The use of nucleotide sequence data to measure...Ch. 22 - Calculate the frequencies of the AA, Aa, and aa...Ch. 22 - Prob. 7PDQ
Ch. 22 -
8. What must be assumed in order to validate the...Ch. 22 - In a population where only the total number of...Ch. 22 -
10. If 4 percent of a population in equilibrium...Ch. 22 -
11. Consider a population in which the frequency...Ch. 22 - If the initial allele frequencies are p = 0.5 and...Ch. 22 -
13. Under what circumstances might a lethal...Ch. 22 - Assume that a recessive autosomal disorder occurs...Ch. 22 -
15. One of the first Mendelian traits identified...Ch. 22 -
16. Describe how populations with substantial...Ch. 22 - Achondroplasia is a dominant trait that causes a...Ch. 22 -
18. A recent study examining the mutation rates...Ch. 22 - A form of dwarfism known as Ellis–van Creveld...Ch. 22 -
20. List the barriers that prevent interbreeding...Ch. 22 - What are the two groups of reproductive isolating...Ch. 22 - Prob. 22PDQCh. 22 -
23. In a recent study of cichlid fish inhabiting...Ch. 22 - What genetic changes take place during speciation?Ch. 22 - Some critics have warned that the use of gene...Ch. 22 - Comparisons of Neanderthal mitochondrial DNA with...
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