Concepts of Genetics (11th Edition)
11th Edition
ISBN: 9780321948915
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino
Publisher: PEARSON
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Chapter 7, Problem 35ESP
In chickens, a key gene involved in sex determination has recently been identified. Called DMRT1, it is located on the Z chromosome and is absent on the W chromosome. Like SRY in humans, it is male determining. Unlike SRY in humans, however, female chickens (ZW) have a single copy while males (ZZ) have two copies of the gene. Nevertheless, it is transcribed only in the developing testis. Working in the laboratory of Andrew Sinclair (a co-discoverer of the human SRY gene), Craig Smith and colleagues were able to “knock down” expression of DMRT1 in ZZ embryos using RNA interference techniques (see Chapter 18). In such cases, the developing gonads look more like ovaries than testes [Nature 461: 267 (2009)]. What conclusions can you draw about the role that the DMRT1 gene plays in chickens in contrast to the role the SRY gene plays in humans?
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In chickens, a key gene involved in sex determination has recently been identified. Called DMRT1, it is located on the Z chromosome and is absent on the W chromosome. Like SRY in humans, it is male determining. Unlike SRY in humans, however, female chickens (ZW) have a single copy while males (ZZ) have two copies of the gene. Nevertheless, it is transcribed only in the developing testis. Working in the laboratory of Andrew Sinclair (a co-discoverer of the human SRY gene), Craig Smith and colleagues were able to “knock down” expression of DMRT1 in ZZ embryos using RNA interference techniques (see Chapter 18). In such cases, the developing gonads look more like ovaries than testes [Nature 461: 267 (2009)]. What conclusions can you draw about the role that the DMRT1 gene plays in chickens in contrast to the role the SRY gene plays in humans?
The development of sex and gender is a good example of a developmental cascade because:
Group of answer choices
Although having an X and a Y chromosome at conception typically leads to the development of testes during prenatal development, this may not lead to typical male genitalia if certain hormones are present later in development
Two people may have the same gonads early in prenatal development but end up with different external genitalia and gender identities as a result of differences in the prenatal environment
All of the options listed here are correct
Having two X chromosomes at conception typically leads to the development of ovaries during prenatal development, which typically leads to high levels of estrogen in puberty, which typically leads to a female gender identity in adulthood
Which of the following is true about sex determination in mammals? Choose all possible answers.
a.) The conversion of the genital ridge into the bipotential gonad requires the Sf1, Wt1, and Lhx9 transcription factors.
b.) Even if one of the transcription factors mentioned in choice a (Sf1, Wt1, and Lhx9) will lose its function, the normal development of either male or female gonads will still push through.
c.) Sry protein binds to the enhancer of the Sox9 gene and elevates expression of this key gene in the ovary-determining pathway.
d.) β-catenin functions to initiate the ovarian pathway of development by activating the genes involved in granulosa cell differentiation.
e.) Sf1 protein prevents the production of Sox9.
Chapter 7 Solutions
Concepts of Genetics (11th Edition)
Ch. 7 - Prob. 1NSTCh. 7 - Campomelic dysplasia (CMD1) is a congenital human...Ch. 7 - Carbon Copy (CC), the first car produced from a...Ch. 7 - Prob. 1CSCh. 7 - Prob. 2CSCh. 7 - Prob. 3CSCh. 7 - Prob. 4CSCh. 7 - HOW DO WE KNOW? In this chapter, we have focused...Ch. 7 - Review the Chapter Concepts list on p. 151. These...Ch. 7 - Prob. 3PDQ
Ch. 7 - Prob. 4PDQCh. 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 - Prob. 23PDQCh. 7 - Prob. 24PDQCh. 7 - Prob. 25PDQCh. 7 - Prob. 26PDQCh. 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 - Prob. 31ESPCh. 7 - In mice, the X-linked dominant mutation Testicular...Ch. 7 - When the cloned cat Carbon Copy (CC) was born (see...Ch. 7 - Prob. 34ESPCh. 7 - In chickens, a key gene involved in sex...Ch. 7 - Prob. 36ESP
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