Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 19, Problem 23P
The yan gene encodes a transcription factor that represses R7 development in the five cells that express Sevenless and are therefore competent to become R7. In yan null mutants, all five cells in each ommatidium can become R7 (just as in sev-RasG12V> transgenic flies; see Fig. 19.7b). The eyes of sev- yan- double null mutants display the yan-> mutant phenotype.
a. | Describe the epistasis relationship between sev- and yan- mutants. |
b. | Based on what you know about the roles of Sevenless and Yan proteins in the signaling pathway (Fig. 19.6), is this the epistatic interaction you would have expected? Explain. |
c. | Epistasis analysis can be performed only if two mutants in genes in the same pathway have different mutant |
d. | The constitutively active RasG12V mutation is epistatic to the sev- null mutation, and so is a yan- null mutation; yet both Ras and Yan function downstream of Sevenless in the signaling pathway. Considering your answer to part (c), explain why this makes sense. |
e. | Suppose that a researcher identifies flies with a dominant constitutively active mutant allele of yan (yanD) that expresses yan even in cells where the Sevenless pathway is activated. Predict the mutant phenotype of the flies. Would you expect yanD to be epistatic to sev- ? to RasG12V? Explain. |
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Given the following Western blot results showing levels of proteins over time in three yeast cell extracts after the induction of high level expression of the CDH1 protein.
WT
GAL-CDH1
GAL-CDH1,
cdc23-1
0 30 60 120 0 30 60 120 0 30 60 120 Time (min)
| Pds1
- Clb2
- Ase1
- Kar2
Note: The GAL-CDH1 indicates that the yeast strain contains a transgenic cdh1 gene under the control of the GAL promoter. This means that the researcher can control expression of that cdh1 gene. In these three experiments (three yeast strains), time O is the point at which GAL-
controlled genes begin to get expressed (WT lacks transgenes).
which is a component of the A
In this experiment, four proteins are being probed for in three different yeast strains (1. wild-type, 2. a strain containing the cdh1 gene under GAL control (see note), and 3. the GAL-CDH1 strain that is also harboring a cdc23 loss of function allele (allele
The upper (larger) band in the Ase1 lanes is non-specific background band; disregard it.…
Given the following Western blot results showing levels of proteins over time in three yeast cell extracts after the induction of high level expression of the CDH1 protein.
WT
GAL-CDH1
GAL-CDH1,
cdc23-1
0 30 60 120 0 30 60 120 0 30 60 120 Time (min)
- Pds1
- Clb2
- Ase1
- Kar2
Note: The GAL-CDH1 indicates that the yeast strain contains a transgenic cdh1 gene under the control of the GAL promoter. This means that the researcher can control expression of that cdh1 gene. In these three experiments (three yeast strains), time 0 is the point at which GAL-
controlled genes begin to get expressed (WT lacks transgenes).
In this experiment, four proteins are being probed for in three different yeast strains (1. wild-type, 2. a strain containing the cdh1 gene under GAL control (see note), and 3. the GAL-CDH1 strain that is also harboring a cdc23 loss of function allele (allele 1), which is a component of the A
The upper (larger) band in the Ase1 lanes is non-specific background band; disregard…
In the module, you have learned about P-element mediated transgenesis in Drosophila and the concept of using transgenes to rescue mutant phenotypes. In the figure below, you will see a wild type fly with its natural eye colour and three mutants with their eye colours changed to vermillion, white and rosy, respectively. A schematic of P-element mediated transgenesis (as shown in the lectures) is also included in the figure. Please inspect the schematic carefully and choose which of the following statements is true:
I.
Injection of the white experimental transgene into the vermillion mutant embryo will not change the vermillion mutant phenotype
II.
Injection of the white experimental transgene in the rosy mutant embryo will change rosy eye colour to red (wild type)
III.
Injection of the white experimental transgene in the white mutant embryo will not change the white mutant phenotype
IV.
Injection of the white experimental transgene in the rosy mutant…
Chapter 19 Solutions
Genetics: From Genes to Genomes
Ch. 19 - Match each of the terms in the left column to the...Ch. 19 - a. If you were interested in the role of a...Ch. 19 - Early C. elegans embryos display mosaic...Ch. 19 - Hypomorphic mutations in the wingless gene of...Ch. 19 - Prob. 5PCh. 19 - In 1932, H. J. Muller suggested a genetic test to...Ch. 19 - a. Explain how you could use worms transformed...Ch. 19 - Suppose you want to determine whether a particular...Ch. 19 - Sevenless is an unusual receptor protein in that...Ch. 19 - Suppose that you generated flies containing a...
Ch. 19 - Drosophila researchers have collected many strains...Ch. 19 - As an alternative to random mutagenesis,...Ch. 19 - A C. elegans nematode gene called par-1 helps to...Ch. 19 - The molecular identity of the fruit fly rugose...Ch. 19 - To determine the focus of action of boss,...Ch. 19 - Suppose a particular gene is required for early...Ch. 19 - Researchers have exploited Minute mutations in...Ch. 19 - Some ts alleles are temperature sensitive during...Ch. 19 - The following figure shows the temperature-shift...Ch. 19 - A temperature-sensitive allele of the gene...Ch. 19 - Hypomorphic alleles of a pleiotropic gene...Ch. 19 - In addition to the maternal effect genes that...Ch. 19 - The yan gene encodes a transcription factor that...Ch. 19 - Recall from Chapter 17 that in Drosophila, sex...Ch. 19 - a. Explain the difference between maternal...Ch. 19 - In the 1920s, Arthur Boycott, working with the...Ch. 19 - The Drosophila mutant screen shown on the...Ch. 19 - Some genes are required both zygotically and...Ch. 19 - How would a human with a mutation in a maternal...Ch. 19 - One important demonstration that Bicoid is an...Ch. 19 - The hunchback gene contains a 5 transcriptional...Ch. 19 - In flies developing from eggs laid by a...Ch. 19 - Wild-type embryos and mutant embryos lacking the...Ch. 19 - The Drosophila even-skipped eve gene has four...Ch. 19 - In Drosophila with loss-of-function mutations...Ch. 19 - It is crucial to the development of Drosophila...Ch. 19 - In the plant Arabidopsis thaliana, every flower is...
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