chapter 21 part 3 COPY

Question 1

GM plants:

Answer 1

Some people think the genetic modification of plants will help feed the ever-growing human population, and overcome environmental issues including excess carbon dioxide production and pollution.
Others have major concerns about the process.

Question 2

Insect resistance in GM soya beans

Answer 2

Soya beans are a major world crop - around 250 million tonnes are produced each year and over half of the plants are from GM strains.
In one such modification, scientists have inserted a gene into soya beans so that they produce the Bt protein.
The Bt protein is toxic to many of the pest insects that attack the plant and is widely used as a pesticide by organic farmers.
One increasingly widely used strain of soya beans has been engineered to be resistant to a common weed killer and to contain Bt protein.
This means farmers can spray to get rid of weeds, making all the resources of light, water, and minerals available to the beans, and they do not need to use pesticides.
These plants should enable farmers to grow a much higher-yield crop of soya beans with less labour and less expense.

Question 3

Benefits and risks of GM crops:
part 1 - pest resistance, disease resistance and herbicide resistance

Answer 3

Question 4

Benefits and risks of GM crops:
part 2 - extended shelf - life, growing conditions, nutritional value and medical uses

Answer 4

Question 5

Patenting and technology transfer
part 1

Answer 5

One of the major concerns about GM crops is that people in less economically developed countries will be prevented from using them by patents and issues of technology transfer.
When someone discovers a new technique or invents something. they can apply for a legal patent, which means that no-one else can use it without payment.
The people who most need the benefits of, for instance, drought- or flood-resistant crops, high yields, and added nutritional value may therefore be unable to afford the GM seed.
They also rely on harvesting seed from one year to plant the next - something that patenting may make impossible.
These concerns are based on evidence.

Question 6

Patenting and technology transfer
part 2

Answer 6

The company that developed the herbicide-resistant and pesticide-producing soya beans, have patented them so farmers can buy the beans from them and grow them to use or sell them for food or processing only in the year they are bought.
They cannot save the seed to grow again the next year - and in 2013 this was upheld in the US Supreme Court.
Some organisations, however, such as the International Rice Research instritiute (IRRI) work to develop engineered rice sepcidfically to support farmers in less economically developed countries with whom they share the technological developments without patent constraints on seed harvesting. For example, they have engineered flood-resistant ‘scuba’ rice, which gives 70-80% of maximum potential yield even if submerged for 2-3 weeks by flooding.

Question 7

GM animals:

Answer 7

It is much harder to produce GM vertebrates, especially animals but scientists are researching the use of microinjections - tiny particles of gold covered in DNA - and modified viruses to carry new genes into animal DNA.
Such techniques are used with a number of goals in mind, including the transfer of disease resistance from one animal to another, or to modify physiology in farmed animals.

Question 8

Some examples of GM animals:

Answer 8

Swine fever-resistant pigs
in 2013 UK scientists successfully inserted a gene from wild African pigs into the early embryos of a European pig strain giving them immunity to otherwise fatal African swine fever

Faster-growing salmon
in the USA, GM Atlantic salmon have received genes from faster-growing Chinook salmon.
The genes cause them to produce growth hormones all year round.
They grow to full adult size in half the time of conventional salmon, making them a very efficient food source.

Question 9

pharming.

Answer 9

One of the biggest uses of genetic engineering so far in animals is in the production of human medicines

Question 10

two aspects to the pharming field of gene technology:

Answer 10

Creating animal models
Creating human proteins

Question 11

Creating animal models

Answer 11

the addition or removal of genes so that animals develop certain diseases, acting as models for the development of new therapies, for example, knockout mice have genes deleted so they are more likely to develop cancer.

Question 12

Creating human proteins part 1

Answer 12

the introduction of a human gene coding for a medically required protein.
Animals are sometimes used because bacteria cannot produce all of the complex proteins made by eukaryotic cells.
The human gene can be introduced into the genetic material of a fertilised cow, sheep, or goat egg, along with a promoter sequence so the gene is expressed only in the mammary glands.

Question 13

Creating human proteins part 2

Answer 13

The fertilised, transgenic female embryo is then returned to the mother.
A transgenic animal is born and when it matures and gives birth, it produces milk.
The milk will contain the desired human protein and can be harvested.

Question 14

There are many potential benefits to people and indeed to animal health of genetic engineering but the process also raises some ethical questions, which include:

Answer 14

Should animals be genetically engineered to act as models of human disease?
Is it right to put human genes into animals?
Is it acceptable to put genes from another species into an animal without being certain it will not cause harm?
Does genetically modifying animals reduce them to commodities?
Is welfare compromised during the production of genetically engineered animals?

Question 15

Gene therapy in humans:

Answer 15

Some human diseases such as CE, haemophilia, and severe combined immunodeficiency (SCIDS) are the result of faulty (mutant) genes.
Scientists are looking at different ways of replacing the faulty allele with a healthy one.
They can remove the desired alleles from healthy cells or synthesise healthy alleles in the laboratory.

Question 16

Somatic cell gene therapy:
part 1

Answer 16

This involves replacing the mutant allele with a healthy allele in the affected somatic (body) cells.
The potential for helping people with a wide range of diseases is enormous.
Until recently there were few success stories as there are problems in getting the healthy alleles into the affected cells, getting the engineered plasmids into the nucleus of the cells, and finally difficulties in starting and maintaining expression of the healthy allele.
Viral vectors are often used.
In recent years, somatic cell gene therapy is beginning to show signs of fulfilling its potential.

Question 17

Somatic cell gene therapy:
part 2:

Answer 17

Successful treatments have been reported for diseases including retinal disease (people have regained some vision), immune diseases, leukaemias, myelomas, and haemophilia.
The first gene therapy has recently (2012) been approved by the European Medicines Agency for lipoprotein lipase deficiency, which can cause severe pancreatitis.
However, somatic cell gene therapy is only a temporary solution for the treated individual.
The healthy allele will be passed on every time a cell divides by mitosis but somatic cells have a limited life, and are replaced from stem cells, which will have the faulty allele.
In addition, a treated individual will still pass the faulty allele on to any children they have.

Question 18

Germ line cell gene therapy: part 1

Answer 18

The alternative to treating the somatic (body) cells of people already affected by a disease is to insert a healthy allele into the germ cells - usually the eggs - or into an embryo immediately after fertilisation (as part of in vitro fertilisation (IVF) treatment).
The individual would be born healthy with the normal allele in place - and would pass it on to their own offspring. This is called germ line cell gene therapy.

Question 19

Germ line cell gene therapy: part 2

Answer 19

Such therapy has been successfully done with animal embryos but is illegal for human embryos in most countries as a result of various ethical and medical concerns.
These concerns include the fact that the potential impact on an individual of an intervention on the germ cells is unknown.
Also, the human rights of the unborn individual could be said to be violated because it is, of course, done without consent and once done the process is irrevocable.
Another major ethical concern is that the technology might eventually be used to enable people to choose desirable or cosmetic characteristics of their offspring.