Concepts of Genetics (12th Edition)
12th Edition
ISBN: 9780134604718
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino, Darrell Killian
Publisher: PEARSON
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Chapter 8, Problem 20PDQ
The mutations called bobbed in Drosophila result from variable reductions (deletions) in the number of amplified genes coding for rRNA. Researchers trying to maintain bobbed stocks have often documented their tendency to revert to wild type in successive generations. Propose a mechanism based on meiotic recombination which could account for this reversion phenomenon. Why would wild-type flies become more prevalent in Drosophila cultures?
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A maternal effect gene in Drosophila, called torso, is found as a recessive allele that prevents the correct development of anterior- and posterior-most structures. A wild-type (homozygous) male iscrossed to a female of unknown genotype. This mating produces 100% larva that are missing theiranterior- and posterior-most structures and therefore die during early development.
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Chapter 8 Solutions
Concepts of Genetics (12th Edition)
Ch. 8 - A human female with Turner syndrome (47, X) also...Ch. 8 - When two plants belonging to the same genus but...Ch. 8 - What is the effect of a rare double crossover (a)...Ch. 8 - Controlling the overgrowth of invasive aquatic...Ch. 8 - Controlling the overgrowth of invasive aquatic...Ch. 8 - Controlling the overgrowth of invasive aquatic...Ch. 8 - HOW DO WE KNOW? In this chapter, we have focused...Ch. 8 - Review the Chapter Concepts list on page 171....Ch. 8 - Define these pairs of terms, and distinguish...Ch. 8 - For a species with a diploid number of 18,...
Ch. 8 - What evidence suggests that Down syndrome is more...Ch. 8 - What evidence indicates that humans with aneuploid...Ch. 8 - Contrast the fertility of an allotetraploid with...Ch. 8 - Describe the origin of cultivated American cotton.Ch. 8 - Predict how the synaptic configurations of...Ch. 8 - Inversions are said to suppress crossing over. Is...Ch. 8 - Contrast the genetic composition of gametes...Ch. 8 - Human adult hemoglobin is a tetramer containing...Ch. 8 - Discuss Ohnos hypothesis on the role of gene...Ch. 8 - What roles have inversions and translocations...Ch. 8 - The primrose, Primula kewensis, has 36 chromosomes...Ch. 8 - Certain varieties of chrysanthemums contain 18,...Ch. 8 - Drosophila may be monosomic for chromosome 4, yet...Ch. 8 - Mendelian ratios are modified in crosses involving...Ch. 8 - Having correctly established the F2 ratio in...Ch. 8 - The mutations called bobbed in Drosophila result...Ch. 8 - The outcome of a single crossover between...Ch. 8 - A couple planning their family are aware that...Ch. 8 - In a cross in Drosophila, a female heterozygous...Ch. 8 - A woman who sought genetic counseling is found to...Ch. 8 - Prob. 25ESPCh. 8 - In a recent cytogenetic study on 1021 cases of...Ch. 8 - A boy with Klinefelter syndrome (47,XXY) is born...Ch. 8 - Prob. 28ESPCh. 8 - A 3-year-old child exhibited some early indication...Ch. 8 - A normal female is discovered with 45 chromosomes,...
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- The genes dumpy wings (dp), clot eyes (cl), and apterous wings (ap) are linked on chromosome II of Drosophila. In a series of two-point mapping crosses, the genetic distances shown below were determined. What is the sequence of the three genes? dp–ap 42 dp–cl 3 ap–cl 39arrow_forwardDrosophila females heterozygous for three recessive mutations, a, b, and c , were crossed to males homozygous for all three mutations.The cross yielded the following results: in the image Q. Construct a linkage map showing the correct order of these genes and estimate the distances between them.arrow_forwardIn a mutant screen in Drosophila, you identified a gene related to memory, as evidenced by the inability of recessive homozygotes to learn to associate a particular scent with the availability of food. Given another line of flies with an autosomal mutation that produces orange eyes, design a series of crosses to determine the map distance between these two loci. You do not need to calculate recombination frequency.arrow_forward
- The genes dumpy wings (dp), clot eyes (cl), and apterous wings(ap) are linked on chromosome II of Drosophila. In a series of twopoint mapping crosses, the genetic distances shown below weredetermined. What is the sequence of the three genes? dp–ap 42dp–cl 3ap–cl 39arrow_forward. With regards to the grasshopper testes experiment, diakinesis is an ideal stage to determine chromosome number due to the degree of condensation of the chromosomes? Count the chromosomes at this stage. Does it represent a diploid or a haploid number?arrow_forwardA maternal effect gene in Drosophila, called torso, is found as a recessive allele that prevents the correct development of anterior- and posterior-most structures. A wild-type (homozygous) male is crossed to a female of unknown genotype. This mating produces 100% larva that are missing their anterior- and posterior-most structures and therefore die during early development. What is the genotype and phenotype of the female fly in this cross? What are the genotypes and phenotypes of the female fly’s parents? Show COMPLETE cross.arrow_forward
- In Drosophila, the genes for eye color, wing shape, and wing length are located on chromosome II. Purple eyes (pr), arc bent wings (a), and vestigial wings (vg) are the mutant forms of the wild type traits red eyes, straight wings, and long wings, respectively. You've discovered some data in your genetics laboratory which indicates that the distance between vg and pr is 12.5 m.u., the distance between a and pr is 44.7 m.u., and the distance between a and vg is 32.2 m.u. From this information, deduce the order of these genes on chromosome II and identify which gene is in the middle. A. a B. pr C. not enough information to tell D. vgarrow_forwardconsider the metaphase (mitosis) chromosome spread of the following related animal species. The first meiotic division in the hybrid animal shows a mixture of paired and single chromosomes. Why do you suppose this occurs? Can you suggest a possible relationship between the mixed chromosomes and the observed sterility of the hybrid?arrow_forwardWhat would you predict to be the phenotype of a Drosophila larva whose mother was homozygous for a loss-of-function allele in the nanos gene?arrow_forward
- In an electrophoretic gel across which is applied a powerful electrical alternating pulsed field, the DNA of the haploid fungus Neurospora crassa (n = 7) moves slowly but eventually forms seven bands, which represent DNA fractions that are of different sizes and hence have moved at different speeds. These bands are presumed to be the seven chromosomes. How would you show which band corresponds to which chromosome?arrow_forwardYou design Drosophila crosses to provide recombinationdata for gene a, which is located on the chromosome shownin Figure 15.12. Gene a has recombination frequencies of14% with the vestigial wing locus and 26% with the browneye locus. Approximately where is a located along thechromosome?arrow_forwardThe genes dumpy (dp), clot (cl), and apterous (ap) are linked on chromosome II of Drosophila. In a series of two-point mapping crosses, the following genetic distances were determined. What is the sequence of the three genes? dp–ap 42 dp–cl 3 ap–cl 39arrow_forward
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