Exam 16: Forward Genetics and Recombinant Dna Technology

If a mutagenesis screen provides some number of alleles shown by complementation analysis to be in the same gene, which of the following is true?

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Question 1

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Design an experiment that uses enhancer trapping to drive the expression of a gene of interest.

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Question 2

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Enhancer trap constructs include a reporter gene that is fused to a weak promoter that, by itself, is insufficient to drive expression of the reporter gene. The construct also requires a mobile element, typically a P element, which allows this basal transcription unit to be inserted into the genome. When the reporter gene is integrated near an enhancer region, the enhancer is "trapped" and the reporter gene is expressed, which allows you to identify spatial regulation by enhancers. In E. coli, a common enhancer trap is P[lacZ], while yeast often uses a P[GAL4] enhancer trap. Enhancer trapping also uses a visible marker to help with easy identification of new insertions. For example, the white gene, which is responsible for wild-type red eye color in Drosophila, is disrupted by an insertion event, creating a white-eyed phenotype. Drosophila also has the benefit of having a large number of readily available fly stocks containing GAL4 insertions, which act as the "drivers." Using one of these stocks, plus a second fly stock containing a UAS DNA sequence followed by your gene of interest, you can simply cross these two lines of flies. This eliminates the need to directly clone transgenic flies with the enhancer linked to your gene and saves a lot of time and resources, making enhancer trapping a relatively easy process.

In Drosophila, mutation screening usually involves use of a balancer chromosome that includes three elements: a set of overlapping inversions, an easily recognized dominant mutation, and a recessive lethal mutation that prevents balancer homozygotes from surviving. Which one, or combination, of these elements is necessary and sufficient to suppress crossovers?

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Question 3

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DNA markers that are found to segregate with a mutation of interest can be used to determine the mutation's distance from the markers by looking at what?

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Question 4

Should we allow (or urge)testing of minor-age children or teens for adult-onset disorders for which there is no treatment or cure?

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Question 5

You have performed a mutagenesis screening in a population of organisms. Describe how you would identify mutations that are dominant. Describe how you would identify mutations that are recessive.

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Question 6

For a contiguous sequence to be most useful in molecular mapping of a particular mutation, what should the contiguous sequence include?

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Question 7

In the process of identifying mutations in animals, dominant mutations can be found after one generation of mating between the mutagenized male organism and wild-type female. To identify the non-sex-linked (autosomal)recessive mutants requires ________ generations.

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Question 8

Suppose a mutagen is used on an inbred population of mice to establish cell lines, each including a different mutant allele, which can then be tested for function. This technique is known as ________.

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Question 9

Besides the obvious fact that chemical mutagens are dangerous to handle, another major disadvantage to their use is that __________.

(Multiple Choice)

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Question 10

In a disease associated with a nucleotide repeat, anticipation is often noticed in subsequent generations, usually associated with a more severe phenotype. Which of the following is a more likely cause of anticipation?

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Question 11

Conditional alleles result in phenotypic differences in permissive as opposed to restrictive conditions. What do these conditions have in common?

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Question 12

A balancer chromosome includes a recessive lethal allele, a marker dominant allele, and ________.

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Question 13

Which of the following would make a human disorder-causing allele or gene easiest to locate?

(Multiple Choice)

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Question 14

The GFP gene is useful as a reporter gene because the cells and tissues with it emit bioluminescence when treated with what, which functions as a substrate?

(Short Answer)

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Question 15

A genetic strategy that starts with knowing the DNA sequence and works toward identifying an associated phenotype is known as ________.

(Short Answer)

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Question 16

If mutagenizing a number of Drosophila results in several observable phenotypes but also in several lethal mutations, does this mean that recessive lethal mutations cannot be studied further?

(Multiple Choice)

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Question 17

You have evidence that a gene, VTE4, of known sequence and well-understood transcriptional regulation, is available from another lab. The product of this gene enables seeds to produce a significantly increased amount of vitamin E from a substrate already produced in Brassica napus, the plant that gives us canola oil. To produce canola oil with increased vitamin E, how would you proceed?

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Question 18

The reasons for using transposon-based mutagenesis include all of the following except __________.

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Question 19

In mapping the HD gene associated with Huntington disease, eventually researchers narrowed down their hunt to four candidate genes within the mapped region. How did they identify one of these as the definitive HD gene?

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Question 20

Showing 1 - 20 of 44

If a mutagenesis screen provides some number of alleles shown by complementation analysis to be in the same gene, which of the following is true?

Design an experiment that uses enhancer trapping to drive the expression of a gene of interest.

DNA markers that are found to segregate with a mutation of interest can be used to determine the mutation's distance from the markers by looking at what?

Should we allow (or urge)testing of minor-age children or teens for adult-onset disorders for which there is no treatment or cure?

You have performed a mutagenesis screening in a population of organisms. Describe how you would identify mutations that are dominant. Describe how you would identify mutations that are recessive.

For a contiguous sequence to be most useful in molecular mapping of a particular mutation, what should the contiguous sequence include?

In the process of identifying mutations in animals, dominant mutations can be found after one generation of mating between the mutagenized male organism and wild-type female. To identify the non-sex-linked (autosomal)recessive mutants requires ________ generations.

Suppose a mutagen is used on an inbred population of mice to establish cell lines, each including a different mutant allele, which can then be tested for function. This technique is known as ________.

Besides the obvious fact that chemical mutagens are dangerous to handle, another major disadvantage to their use is that __________.

In a disease associated with a nucleotide repeat, anticipation is often noticed in subsequent generations, usually associated with a more severe phenotype. Which of the following is a more likely cause of anticipation?

Conditional alleles result in phenotypic differences in permissive as opposed to restrictive conditions. What do these conditions have in common?

A balancer chromosome includes a recessive lethal allele, a marker dominant allele, and ________.

Which of the following would make a human disorder-causing allele or gene easiest to locate?

The GFP gene is useful as a reporter gene because the cells and tissues with it emit bioluminescence when treated with what, which functions as a substrate?

A genetic strategy that starts with knowing the DNA sequence and works toward identifying an associated phenotype is known as ________.

If mutagenizing a number of Drosophila results in several observable phenotypes but also in several lethal mutations, does this mean that recessive lethal mutations cannot be studied further?

The reasons for using transposon-based mutagenesis include all of the following except __________.

In mapping the HD gene associated with Huntington disease, eventually researchers narrowed down their hunt to four candidate genes within the mapped region. How did they identify one of these as the definitive HD gene?

The Molecular Basis of Heredity, Variation, and Evolution

Transmission Genetics

Cell Division and Chromosome Heredity

Gene Interaction

Genetic Linkage and Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophages

Dna Structure and Replication

Molecular Biology and Transcription and Rna Processing

The Molecular Biology of Translation

The Integration of Genetic Approaches: Understanding Sickle Cell Disease

Chromosome Structure

Gene Mutation, Dna Repair, and Homologous Recombination

Chromosome Aberrations and Transposition

Regulation of Gene Expression in Bacteria and Bacteriophages

Regulation of Gene Expression in Eukaryotes

Applications of Recombinant Dna Technology and Reverse Genetics

Genomics: Genetics From a Whole-Genome Perspective

Cytoplasmic Inheritance and the Evolution of Organelle Genomes

Developmental Genetics

Genetic Analysis of Quantitative Traits

Population Genetics and Evolution

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