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 7, Problem 20PDQ
Cat breeders are aware that kittens expressing the X-linked calico coat pattern and tortoiseshell pattern are almost invariably females. Why are they certain of this?
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Colorblindness is an X-linked trait found in humans. What are the chances that a colorblind man will pass it on to his son? Please explain.
Males of many diploid species (like us) have X and Y sex chromosomes. They are hemizygous for most X-
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Chapter 7 Solutions
Concepts of Genetics (12th Edition)
Ch. 7 - Campomelic dysplasia (CMD1) is a congenital human...Ch. 7 - Carbon Copy (CC), the first car produced from a...Ch. 7 - Gender is someones conscious and unconscious...Ch. 7 - Gender is someones conscious and unconscious...Ch. 7 - HOW DO WE KNOW? In this chapter, we have focused...Ch. 7 - Review the Chapter Concepts list on p. 151. These...Ch. 7 - Distinguish between the concepts of sexual...Ch. 7 - Contrast the XX/XY and XX/X0 modes of sex...Ch. 7 - Describe the major difference between sex...Ch. 7 - How do mammals, including humans, solve the dosage...
Ch. 7 - The phenotype of an early-stage human embryo is...Ch. 7 - What specific observations (evidence) support the...Ch. 7 - Describe how nondisjunction in human female...Ch. 7 - An insect species is discovered in which the...Ch. 7 - When cows have twin calves of unlike sex...Ch. 7 - An attached-X female fly, XXY (see the Insights...Ch. 7 - Assume that on rare occasions the attached X...Ch. 7 - It has been suggested that any male-determining...Ch. 7 - What is a Barr body, and where is it found in a...Ch. 7 - Indicate the expected number of Barr bodies in...Ch. 7 - Define the Lyon hypothesis.Ch. 7 - Can the Lyon hypothesis be tested in a human...Ch. 7 - Predict the potential effect of the Lyon...Ch. 7 - Cat breeders are aware that kittens expressing the...Ch. 7 - In mice, the Sry gene (see Section 7.2) is located...Ch. 7 - The genes encoding the red-and...Ch. 7 - What is the role of the enzyme aromatase in sexual...Ch. 7 - In the wasp Bracon hebetor, a form of...Ch. 7 - The Amami spiny rat (Tokudaia osimensis) lacks a Y...Ch. 7 - In mice, the X-linked dominant mutation Testicular...Ch. 7 - When the cloned cat Carbon Copy (CC) was born (see...Ch. 7 - In reptiles, sex determination was thought to be...Ch. 7 - In chickens, a key gene involved in sex...
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- Analysis of X-Linked Dominant and Recessive Traits In the eighteenth century, a young boy with a skin condition known as ichthyosis hystrix gravior was identified. The phenotype of this disorder includes thickening of skin and the formation of loose spines that are sloughed off periodically. This man married and had six sons, all of whom had the same condition. He also had several daughters, all of whom were unaffected. In all succeeding generations, the condition was passed on from father to son. What can you theorize about the location of the gene that causes ichthyosis hystrix gravior?arrow_forwardPredict the probability (using a Punnett square) of producing an offspring affected by a single gene X-linked mutation given the genotype of the parents. Compare these crosses in two cases: where the mutant allele is “A” vs where the mutant allele is “a” (XAXA x XaY) (XAXa x XAY) (XAXa x XaY) (XaXa x XAY) (XaXa x XaY). Include gender in the phenotype.arrow_forwardPlease provide detailed explanationarrow_forward
- Although most tortoiseshell cats are female, a litter of kittens will occasionally contain a male tortoiseshell. Which of the following can explain tortoiseshell coat color in a male kitten? Please explain in detail. The male kitten has an extra Y chromosome The male kitten has an extra X chromosome The male kitten has no X chromosome The male kitten cannot carry out X-inactivationarrow_forwardAn attached-X female fly, XX ¬Y (see the “Insights and Solutions” box), expresses the recessive X-linked white-eye mutation. It is crossed to a male fly that expresses the X-linked recessive miniature-wing mutation. Determine the outcome of this cross in terms of sex, eye color, and wing size of the offspring.arrow_forwardLet’s suppose that two different X-linked genes exist in mice,designated with the letters N and L. Gene N exists in a dominant,normal allele and in a recessive allele, n, that is lethal. Similarly,gene L exists in a dominant, normal allele and in a recessive allele,l, that is lethal. Heterozygous females are normal, but males thatcarry either recessive allele are born dead. Explain whether or notit would be possible to map the distance between these two genesby making crosses and analyzing the number of living and deadoffspring. You may assume that you have strains of mice in whichfemales are heterozygous for one or both genes.arrow_forward
- Consider 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_forwardAn attached-X female fly, XXn Y (see the “Insights and Solutions”box), expresses the recessive X-linked white-eye phenotype. It is crossed to a male fly that expresses the X-linked recessive miniature wing phenotype. Determine the outcome of this cross in terms of sex, eye color, and wing size of the offspring.arrow_forwardPls answer fastarrow_forward
- A 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_forwardPlease take a look at the attachment.arrow_forward. In humans, hemophilia is an X-linked recessive gene and will only be expressed in females if they are homozygous for this gene. However, in some rare cases, a heterozygote becomes hemophilic. Explain how this incident happens and why will there be skewed X-inactivation?arrow_forward
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