Exam 14: Regulation of Gene Expression in Eukaryotes

In TILLING, a population of inbred organisms is mutagenized to saturation. DNA from mutagenized lines is isolated and amplified by PCR. PCR products are denatured and allowed to reanneal and then treated with an endonuclease. Why is the denaturation/re- annealing step important for the detection of mutant alleles?

Why is only a fraction of an organism's genes represented in any cDNA library?

Why are conditional alleles useful in studying genes with functions in essential cell processes?

A gene, VTE4, from the sunflower of known sequence and well- understood transcriptional regulation, is available from another lab. The product of this gene enables sunflowers to to produce a significantly increased amount of vitamin E from a substrate produced in all plants. The plant Brassica napus is harvested for canola oil. To produce canola oil with increased vitamin E, how would you proceed?

A friend of yours claims to have identified a gene that causes a human disease! Your friend says that they have sequenced the DNA of someone with the disorder and compared that to a healthy individual. They found a nucleotide difference in a gene called Hsr12 that encodes a protein that functions cell- to- cell communication. What is wrong with your friends claim?

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

In an organism, X, it is found to be impossible to generate loss- of- function mutants for most genes. There is an alternative method of introducing random mutations that can later be screened for the gene(s) in question. This can be accomplished by using insertions due to what genetic entities?

A researcher wants to mutagenize an organism. She is not in need of a large number of mutants but is more concerned with being able to find and then to amplify the mutated sequence. Which of the following would therefore be more useful?

Libraries of insertion strains can be screened, primarily by which common technique, to identify mutations in a gene of interest?

If an experimenter wants to use the GFP method but needs to detect the presence or absence of several proteins at the same time, he can take advantage of mutational variants of GFP that emit what?

If a gene in Drosophila is expressed only in imaginal disc (A) when it begins to differentiate, it is referred to as a homeotic gene. Recessive mutations in such genes often result in loss of function so that the structure does not develop. If a transgenic organism is made in which the gene is expressed in a different imaginal, disc (B), what is the predicted result?

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

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?

In a given situation, reduced or missing function in gene A results in a viable but noticeable phenotype. The same is true for gene B. However, when both gene A and gene B products are reduced or missing in the same organism, the result is lethality. What is this called?

In reverse genetics, what is the correct order in which the experimenter proceeds?

Reporter genes such as GFP can be integrated into a native gene to study the expression pattern of a target gene. If a researcher wishes to make a fusion of the GFP protein to the protein expressed by the target gene, where must the GFP gene integrate?

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

To introduce dsRNA into C. elegans, it is enough just to dip the worms into media that includes E. coli containing the dsRNA because __________ .

EMS (ethylmethane sulfonate) is mutagenic because .

Genes for regulatory elements, such as creb, were found to be important in animal learning. Which of the following would increase the probability that such an element is studied throughout the animal kingdom?