Question 1

Ralph, a 57-year-old man, was diagnosed with colon cancer. His oncologist discussed the use of radiation and chemotherapy as treatments for this cancer and explained that each of these therapies kills actively dividing normal and cancer cells, causing debilitating side effects. Ralph decided to carefully review his options and went for a second opinion to a cancer clinic at a major teaching hospital. There he learned that researchers in a synthetic biology program were testing the use of genetically modified E. coli cells that selectively invade and kill cancer cells, with no effects on normal cells. Ralph decided to participate in this trial, and at an appointment to learn about the details, he was informed that he would be part of a Phase III trial, comparing the effects of the modified bacterial cells against conventional chemotherapy. As part of the trial, he would be randomly assigned to receive one or the other treatment. He was disappointed to learn this, because he assumed that he would receive the bacterial therapy.
What are Ralph's options at this point?

Accepted Answer

Ralph's options when entering a Phase III clinical trial would be receive either the control treatment (conventional chemotherapy), or to receive the genetically modified E. coli treatment. While this would be disappointing for someone seeking alternative therapies, if the E. coli therapy were significantly more effective and less damaging than conventional chemotherapy, the option would eventually be allowed to all participants of the study.

Question 2

In this chapter, we focused on a number of interesting applications of genetic engineering, genomics, and biotechnology. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions:
(a) What experimental evidence confirms that we have introduced a useful gene into a transgenic organism and that it performs as we anticipate?
(b) How can we use DNA analysis to determine that a human fetus has sickle-cell anemia?
(c) How can DNA microarray analysis be used to identify specific genes that are being expressed in a specific tissue?
(d) How are GWAS carried out, and what information do they provide?
(e) What are some of the technical reasons why gene therapy is difficult to carry out effectively?

Accepted Answer

The answer of In this chapter, we focused on a...

Question 3

Ralph, a 57-year-old man, was diagnosed with colon cancer. His oncologist discussed the use of radiation and chemotherapy as treatments for this cancer and explained that each of these therapies kills actively dividing normal and cancer cells, causing debilitating side effects. Ralph decided to carefully review his options and went for a second opinion to a cancer clinic at a major teaching hospital. There he learned that researchers in a synthetic biology program were testing the use of genetically modified E. coli cells that selectively invade and kill cancer cells, with no effects on normal cells. Ralph decided to participate in this trial, and at an appointment to learn about the details, he was informed that he would be part of a Phase III trial, comparing the effects of the modified bacterial cells against conventional chemotherapy. As part of the trial, he would be randomly assigned to receive one or the other treatment. He was disappointed to learn this, because he assumed that he would receive the bacterial therapy.
Should he reconsider and try radiation and chemotherapy instead?

Accepted Answer

Ralph can either reconsider and receive radiation/chemotherapy instead, or enter the clinical trial. At this point, his options are equivalent, worst case scenario in the clinical trial; he will receive the chemotherapy option (which he would receive should he reconsider). Best case scenario, he will receive the experimental therapy which he believes is better for the overall person. It would probably be in Ralph's best interests to continue with the clinical trial.

Question 4

Review the Chapter Concepts list. Most of these center on applications of genetic technology that are becoming widespread. Write a short essay that summarizes the impacts that genomic applications are having on society and the ethical issues presented by these applications.
▪Recombinant DNA technology, genetic engineering, and biotechnology have revolutionized medicine and agriculture.
▪Genetically modified plants and animals can serve as bioreactors to produce therapeutic proteins and other valuable protein products.
▪Genetic modifications of plants have resulted in herbicide- and pest-resistant crops, and crops with improved nutritional value; similarly, transgenic animals are being created to produce therapeutic proteins and to protect animals from disease.
▪A synthetic genome has been assembled and transplanted into a donor bacterial strain, elevating interest in potential applications of synthetic biology.
▪Applications of recombinant DNA technology and genomics have become essential for diagnosing genetic disorders, determining genotypes, and scanning the human genome to detect diseases.
▪Genome-wide association studies (GWAS) scan for hundreds or thousands of genetic differences in an attempt to link genome variations to particular traits and diseases.
▪Medical clinics are adopting whole genome sequencing of an individual's DNA for disease diagnosis and treatment.
▪Computational services for predicting offspring based on a couple's genetics are being advertised to consumers.
▪Almost all applications of genetic engineering and biotechnology present unresolved ethical dilemmas that involve important moral, social, and legal issues.

Accepted Answer

The answer of Review the Chapter Concepts list. Most of...

Question 5

Ralph, a 57-year-old man, was diagnosed with colon cancer. His oncologist discussed the use of radiation and chemotherapy as treatments for this cancer and explained that each of these therapies kills actively dividing normal and cancer cells, causing debilitating side effects. Ralph decided to carefully review his options and went for a second opinion to a cancer clinic at a major teaching hospital. There he learned that researchers in a synthetic biology program were testing the use of genetically modified E. coli cells that selectively invade and kill cancer cells, with no effects on normal cells. Ralph decided to participate in this trial, and at an appointment to learn about the details, he was informed that he would be part of a Phase III trial, comparing the effects of the modified bacterial cells against conventional chemotherapy. As part of the trial, he would be randomly assigned to receive one or the other treatment. He was disappointed to learn this, because he assumed that he would receive the bacterial therapy.
Or should he enroll on the chance that he would receive therapy using the genetically modified bacteria and that it would be more effective than conventional therapy?

Accepted Answer

Ralph should enroll in the clinical trial. If he were to reconsider, he would receive the chemotherapy (which he has a 50% chance of receiving in the trial). Therefore, Ralph can only benefit from entering the trial, because he also has 50% of receiving the experimental treatment therefore that would be best option for him.

Question 6

One of the main safety issues associated with genetically modified crops is the potential for allergenicity caused by introducing an allergen or by changing the level of expression of a host allergen. Based on the observation that common allergenic proteins often contain identical stretches of a few (six or seven) amino acids, researchers developed a method for screening transgenic crops to evaluate potential allergenic properties (Kleter Peijnenburg, 2002. BMC Struct. Biol. 2: 8). How do you think they accomplished this?

Accepted Answer

The answer of One of the main safety issues associated...

Question 7

Why are most recombinant human proteins produced in animal or plant hosts instead of bacterial host cells?

Accepted Answer

The answer of Why are most recombinant human proteins produced...

Question 8

There are more than 1000 cloned farm animals in the United States. In the near future, milk from cloned cows and their offspring (born naturally) may be available in supermarkets. These cloned animals have not been transgenically modified, and they are no different than identical twins. Should milk from such animals and their natural-born offspring be labeled as coming from cloned cows or their descendants? Why?

Accepted Answer

The answer of There are more than 1000 cloned farm...

Question 9

One of the major causes of sickness, death, and economic loss in the cattle industry is Mannheimia haemolytica , which causes bovine pasteurellosis, or shipping fever. Noninvasive delivery of a vaccine using transgenic plants expressing immunogens would reduce labor costs and trauma to livestock. An early step toward developing an edible vaccine is to determine whether an injected version of an antigen (usually a derivative of the pathogen) is capable of stimulating the development of antibodies in a test organism. The following table assesses the ability of a transgenic portion of a toxin (Lkt) of M. haemolytica to stimulate development of specific antibodies in rabbits.
  *Lkt50 is a smaller derivative ofLkt that lacks all hydrophobic regions. + indicates at least 50 percent neutralization of toxicity of Lkt; - indicates no neutralization activity.
Source: Modified from Lee et al. 2001. Infect. and Immunity 69: 5786-5793.
(a) What general conclusion can you draw from the data?
(b) With regards to development of a usable edible vaccine, what work remains to be done?

Accepted Answer

The answer of One of the major causes of sickness,...

Question 10

Describe how the team from the J. Craig Venter Institute created a synthetic genome. How did they demonstrate that the genome converted the recipient strain of bacteria into a different strain?

Accepted Answer

The answer of Describe how the team from the J....

Question 11

Suppose you develop a screening method for cystic fibrosis that allows you to identify the predominant mutation ?508 and the next six most prevalent mutations. What must you consider before using this method to screen a population for this disorder?

Accepted Answer

The answer of Suppose you develop a screening method for...

Question 12

Sequencing the human genome and the development of microarray technology promise to improve our understanding of normal and abnormal cell behavior. How are microarrays dramatically changing our understanding of complex diseases such as cancer?

Accepted Answer

The answer of Sequencing the human genome and the development...

Question 13

A couple with European ancestry seeks genetic counseling before having children because of a history of cystic fibrosis (CF) in the husband's family. ASO testing for CF reveals that the husband is heterozygous for the ? 508 mutation and that the wife is heterozygous for the R117 mutation. You are the couple's genetic counselor. When consulting with you, they express their conviction that they are not at risk for having an affected child because they each carry different mutations and cannot have a child who is homozygous for either mutation. What would you say to them?

Accepted Answer

The answer of A couple with European ancestry seeks genetic...

Question 14

When genome scanning technologies become widespread, medical records will contain the results of such testing. Who should have access to this information? Should employers, potential employers, or insurance companies be allowed to have this information? Would you favor or oppose having the government establish and maintain a central database containing the results of individuals' genome scans?

Accepted Answer

The answer of When genome scanning technologies become widespread, medical...

Question 15

What limits the use of differences in restriction enzyme sites as a way of detecting point mutations in human genes?

Accepted Answer

The answer of What limits the use of differences in...

Question 16

Might it make sense someday to sequence every newborn's genome at the time of birth? What are the potential advantages and concerns of this approach?

Accepted Answer

The answer of Might it make sense someday to sequence...

Question 17

What is the main purpose of genome-wide association studies (GWAS)? How can information from GWAS be used to inform scientists and physicians about genetic diseases?

Accepted Answer

The answer of What is the main purpose of genome-wide...

Question 18

The family of a sixth-grade boy in Palo Alto, California, was informed by school administrators that he would have to transfer out of his middle school because they believed his mutation of the CFTR , which does not produce any symptoms associated with cystic fibrosis, posed a risk to other students at the school who have cystic fibrosis. After missing 11 days of school, a settlement was reached to have the boy return to school. Based on what you know about GINA, the Genetic Information Nondiscrimination Act, what ethical problems might you associate with this example?

Accepted Answer

The answer of The family of a sixth-grade boy in...

Question 19

Dominant mutations can be categorized according to whether they increase or decrease the overall activity of a gene or gene product. Although a loss-of-function mutation (a mutation that inactivates the gene product) is usually recessive, for some genes, one dose of the normal gene product, encoded by the normal allele, is not sufficient to produce a normal phenotype. In this case, a loss-of-function mutation in the gene will be dominant, and the gene is said to be haploinsufficient. A second category of dominant mutation is the gain-of-function mutation, which results in a new activity or increased activity or expression of a gene or gene product. The gene therapy technique currently used in clinical trials involves the "addition" to somatic cells of a normal copy of a gene. In other words, a normal copy of the gene is inserted into the genome of the mutant somatic cell, but the mutated copy of the gene is not removed or replaced. Will this strategy work for either of the two aforementioned types of dominant mutations?

Accepted Answer

The answer of Dominant mutations can be categorized according to...

Question 20

In 2013 the actress Angelina Jolie elected to have prophylactic double-mastectomy surgery to prevent breast cancer based on a positive test for mutation of the BRCA1 gene. What are some potential positive and negative consequences of this high-profile example of acting on the results of a genetic test?

Accepted Answer

The answer of In 2013 the actress Angelina Jolie elected...

Quiz 22: Applications and Ethics of Genetic Engineering and Biotechnology