NESA Biology Biotechnology

A plant biotechnology that is of benefit to society is recombinant DNA technology eg when used to produce Bt corn or Bt cotton.

Recombinant DNA technology has many ethical implications. For example, Bt corn seeds cost money to purchase each season, while farmers using normal corn seeds can regrow their crops each year from their own seeds. This leads to inequalities in who has access to these GM seeds, and thus access to markets to sell their products.

The use of selective breeding/hybridisation is a type of biotechnology used in animals eg hybridisation of dairy cows to produce greater milk yielding cows. This has ethical implications for example, the side-effect of continuously selecting for greater milk yield has been a decrease in fertility amongst these cows, and may affect quality of life for cows.

However, there are also many benefits to society of the use of recombinant DNA technology or selective breeding/hybridisation. For example:

• the production of more food like Bt corn which can allow the human population to continue to grow, or greater milk availability for consumers in society
• greater yields for farmers, leading to increased profits and quality of life for farmers.

For example: Changing a species' DNA may result in unforeseen consequences.

To genetically modify bacteria using recombinant DNA technology, first isolate a suitable gene, which must be a gene that produces an enzyme that digests oil. Choose a suitable bacterium for genetic modification (one that can survive in aquatic environments). Use the same restriction enzyme to remove the gene from the host and insert it into a plasmid. Amplify the target gene in the plasmid or by polymerase chain reaction (PCR), and insert the gene into the target bacteria. Transform the bacteria using heat shock, and check the ability of the bacteria to reproduce and produce the gene product.

The advantages of this use include the ability to use genes from other species to achieve outcomes not possible via natural processes. After development, it is easy and fast to produce and supply transgenics in large quantities; and microorganisms are easy to transport, handle, and store.

However, disadvantages include that transgenic organisms could have a negative impact on other organisms or the environment, such as oil-digesting bacteria taking over and displacing natural bacteria. There is also the risk of gene transfer to other organisms.

A mutation is a permanent change to DNA that occurs at random. It changes one allele to another or creates new alleles.

The significance of changes made by mutation is that they can have deleterious effects on individuals. Mutations have a limited effect on allele frequencies because the rate of mutation is low, but they are the source of all genetic variation, alleles, and biological diversity. Other evolutionary processes are dependent on this variation, and populations cannot evolve without genetic variation.

Genetic drift involves the random death of individuals, leading to random or chance changes in allele frequencies. It has the biggest effect in small populations.

The significance of changes made by genetic drift is that it can result in the loss of advantageous alleles. This places populations at risk of extinction due to an inability to adapt.

Human DNA is incorporated with bacterial DNA.

Researchers would work backwards from the amino acid sequence to determine the possible mRNA or DNA. The DNA sequence might differ due to the code being redundant or degenerate OR the natural gene would include introns.

A suitable answer was that the steps to clone and express the gene in bacteria are as follows.

• Isolate human insulin gene from human or artificially synthesise human insulin gene from known sequence.
• Insulin gene inserted into plasmid using restriction enzymes to cut and ligases to join to form recombinant plasmid, which are then placed back into bacteria. These bacteria are then grown in culture.

Some suitable ethical responses were:

• Researchers should stop the clinical trial and people who are being given the animal insulin should be offered the more effective recombinant version of the insulin.
• Stop production of insulin from animals to protect their welfare.
• Release information to public to increase informed decision.

The role of organelles involved in the export of ovalbumin include:

• Rough endoplasmic reticulum transports protein to Golgi, which packages it into vesicles.
• Vesicles move to and fuse with the plasma membrane.
• Content is released by exocytosis.
• Mitochondria provide energy.

Following are two possible answers

1. Ethical concern: intensive farming methods – welfare of the chickens

• Cause: Chickens living in cramped conditions are unable to behave naturally and become stressed.
• Effect: Increased disease, or chickens may peck at one another and cause injury or early death of chickens.

Plus:

• Ethical concept: respect/non-maleficence/beneficence/justice.
• Solution: Providing areas for the chickens to roam during the day. / Providing better diet for the chickens. / Regulations to ensure chickens are looked after.

or

• Ethical approach: consequences-based
• Solution: Ensuring that the positives of increased ovalbumin for humans outweigh the negative impacts on chickens by improving the housing of chickens.

or

• Ethical concept: integrity; Ethical approach: duty- and/or rule-based / virtues-based
• Solution: Chicken farmers follow the guidelines for looking after chickens’ welfare. / Farmers do not cut corners. / Farmers act with good intentions.

2. Ethical concern: the use of recombinant technology

• Cause: Protein produced is not natural. / People uncomfortable consuming products made by modified DNA.
• Effect: Causes harm to humans. / Will ovalbumin be available to everyone?

Plus:

• Ethical concept: beneficence/non-maleficence; Ethical approach: Duty- and/or rules-based
• Solution: Ensuring all laboratories transferring the plasmids are accredited so chance of plasmids being transferred to another organism is small / not likely.

or

• Ethical concept: respect
• Solution: providing information to the general public on the benefits of changing the genome of bacteria / transparent labelling of recombinant ovalbumin

An acceptable answer was one of the following:

• genetically modified (GM) cotton is transgenic as it contains genes from other species OR bacteria.
• GM canola is transgenic as it contains genes from other species OR bacteria.
• GM safflower is not transgenic as it does not contain genes from another species.

An acceptable answer was one of the following:

• use a different herbicide that the GM canola is not resistant to
• remove by mowing
• pick the GM canola growing by the side of the road by hand
• use controlled burning.

Social implication

The correct answer was any one of the following:

• Farmers who grow non-GM canola may sell more canola and the farmer may have an improved quality of life OR may sell less canola and have a decreased quality of life.
• Improved nutrition for consumers and therefore less demand on the health system.
• More people have access to better nutrition as GM canola is cheaper OR more accessible than fish.
• There could be a decreased consumption of fish, which results in fish farmers making less money and having a lower quality of life.
• Consumers may not want to consume GM food. This could lead to consumers not buying enough GM canola and farmers having a lower quality of life.

Biological implication

Accepted responses included any one of the following:

• Possible crossbreeding with non-GM canola crops leading to a change in genome of the crops.
• Potential lack of genetic variation within the GM canola crop. All GM canola plants could then die if there is a change in a selection pressure.
• Consumers may not want to eat or purchase any GM products as these consumers are concerned it is not safe to eat.
• Less fish consumed reduces overfishing, leading to an increase in the fish population.
• Improved nutrition for consumers improves health outcomes for consumers.

The conventional vaccines contained the dead or inactivated version of the pathogen. This resulted in the production of memory cells or faster and larger antibody production.

mRNA vaccines contain mRNA, allowing the individual to create the antigen.

mRNA vaccines can be quickly produced in order to treat different cancers, resulting in the production of antibodies specific to cancer and not to other cells.

Scientists identify a gene that acts as a template and create a complementary sgRNA strand that binds with Cas9. sgRNA then guides Cas9 to the target gene.

The codon sequence changes, leading to amino acid sequence changes and an early stop codon or a non-functional protein produced.

The manufacture of bioethanol arises from the production of ethanol through anaerobic fermentation. This process involves the breakdown of glucose into ethanol in the absence of oxygen.

To produce the genetically modified (GM) mosquitoes, it is necessary to transfer the SERPINE 1 gene from a human to the mosquito using recombinant DNA technology. Restriction enzymes are used to cut the SERPINE 1 gene from a human cell chromosome. A bacterial plasmid (circular DNA) is opened using the same restriction enzymes and the SERPINE 1 gene is inserted and attached using DNA ligase. The bacteria then reproduce, producing multiple copies of the SERPINE 1 gene. The gene can then be delivered into the mosquitos. This can be done by micro-injection into mosquito egg cells, so that the mosquito which develop from the egg will contain the SERPINE 1 gene, which will allow the mosquito to express PAI-1.

In recombinant DNA technology, selected genes can be cut and pasted from one organism into another using, for example, ligase enzymes. The human insulin producing gene has been transferred into bacteria, allowing for increased production of insulin, benefitting sufferers of diabetes, who can access insulin more readily and cheaply. This means that diabetes patients have a greater life span.

Genetic technologies such as CRISPR can be used for controlling pest populations including insects that cause diseases in both humans and other animals. By controlling the number of disease causing insects eg mosquitoes that cause dengue fever, we can significantly reduce the incidence of the vector-borne diseases. This would result in healthier populations and reduced stress on the health care system.

These technologies have largely been beneficial to society, improving access to drugs, the life expectancy and quality of life for many people.