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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Chapter 19, Problem 6P
In 1932, H. J. Muller suggested a genetic test to determine whether a particular mutation whose phenotypic effects are recessive to wild type is a null (amorphic) allele or is instead a hypomorphic allele of a gene. Muller’s test was to compare the
In a study using Muller’s test, investigators examined two recessive, loss-of-function mutant alleles of rugose named rg41 and rgγ3 . The eye morphologies displayed by flies of several genotypes are indicated in the following table. Df(1) JC70 is a large deletion that removes rugose and several genes to either side of it.
| a. | Which allele (rg41 or rgγ3) is stronger (that is, which causes the more severe mutant phenotype)? |
| b. | Which allele directs the production of higher levels of functional Rugose protein? |
| c. | How would Muller’s test discriminate between a null allele and a hypomorphic allele? Suggest a theoretical explanation for Muller’s test. Based on the results shown in the table, is either of these two mutations likely to be a null allele of rugose? If so, which one? |
| d. | Explain why an investigator would want to know whether a particular rg allele was amorphic or hypomorphic. |
| e. | Suppose that a hypermorphic rg allele exists (rghyper) that causes rough eyes due to an excess of cone cells. Could you use Muller’s genetic method to determine that the dominant allele is hypermorphic? Explain. |
| f. | Suppose an antimorphic rg allele exists (rganti). Can you think of a way to determine if a dominant mutation is antimorphic? (Hint: Assume that in addition to the chromosome with a deletion that deletes rg, a chromosome with a duplication that includes the wild-type rg gene is available.) |
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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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