Using Recombinant DNA

Biology: AQA A Level, topic 8.4.5

Uses

Recombinant DNA has a variety of applications. These applications can be hugely beneficial in combating a number of humanitarian issues. These include:

Genetically modified crops

Recombinant DNA can be used to genetically modify crops to improve their yield.
Traits that can be improved include -
Resistance to disease.
Tolerance to the application of herbicides and pesticides.
Tolerance of adverse environmental conditions (e.g. drought).

Genetically modified livestock

Recombinant DNA can be used by farmers to make the production of meat more economically viable.
Traits that can be improved include -
Grow faster and larger.
Resistance to disease.

Increased nutritional value

Recombinant DNA can be used to increase the nutritional value of food.
E.g. Rice has been genetically modified to contain Vitamin A. Vitamin A is a common deficiency in Asian countries where rice is widely consumed.

Treating diseases

Recombinant DNA can be used to produce medicine and hormones to treat diseases.
E.g. Individuals with type I diabetes used to be given pig insulin to control their blood sugar levels. Now human insulin is created using genetically modified bacteria.

Industry

Recombinant DNA can be used to manufacture enzymes.
These enzymes can be used in industry.
E.g. Rennet is an enzyme traditionally taken from the stomach of young mammals like calves to produce cheese. It is now possible to make rennet using genetically engineered bacteria.

Ethical Concerns

Although recombinant DNA technology can be hugely beneficial, there are concerns raised by environmentalists and anti-globalisation activists in opposition to the use of recombinant DNA technology.

Spread of genes

Genetically modified (GM) crops and livestock are produced when a beneficial gene is inserted into their genome to improve a certain trait.
The genes could be transferred into other organisms where it is harmful.
E.g. A gene for herbicide resistance could be passed on to a weed, or a gene for antibiotic resistance to pathogenic bacteria.
Genes from genetically engineered (transgenic) crops could also spread to organic crops.

Unforeseen impacts

Genetic modifications to an organism could have unforeseen effects and disrupt normal gene function.
The use of genetically engineered organisms could lead to a reduction in the variety in populations.
If variety in a population decreases, biodiversity also decreases.
Low biodiversity can have negative impacts (e.g. extinction is more likely).

Economic consequences

There could be economic consequences for some countries if genetically engineered crops can be grown in different countries where previously it was not possible.
Companies who are able to invest more money in recombinant DNA technology may out-compete others.

Medical uses

Some activists are concerned that using recombinant DNA in medicine could lead to unethical uses of genetic engineering.
E.g. Selecting specific traits in offspring (designer babies).

Gene Therapy

Gene therapy is a genetic engineering technique used to cure disease.

Procedure

Gene therapy involves the introduction of a target gene (the gene that confers a beneficial trait) into the genome.
The genome has been transformed.
The target gene is then transcribed and translated to produce the desired protein.
The protein counteracts the effect of a disease that is caused by a mutation.

Allele interactions

Gene therapy is used to treat diseases that are caused by a mutation in a gene.
The way that gene therapy is used depends on the allele interactions of the gene that causes the disease.
If the mutation is in the recessive allele, a wild-type (typical of the species) dominant allele is inserted into the genome. The dominant allele counteracts the mutant alleles.
If the mutation is in the dominant allele, an allele that 'silences' the mutant allele is inserted in the genome.

Vectors

Gene therapy uses vectors to insert the target gene into the genome.
Vectors transport allow the gene to be taken up by the cells of the host. The genome is then transformed.
Types of vector include plasmids and bacteriophages.

Types of gene therapy

There are two types of gene therapy -
Somatic therapy - altering of alleles in adult body cells.
Germline therapy - altering of alleles in sex cells. This is illegal in humans.

Test yourself on Using Recombinant DNA

Which of these is NOT a trait that could be improved in genetically modified livestock?
What are some of the concerns raised with recombinant DNA?
Which of the following statements about ethical concerns are true?
Which of these is NOT an ethical concern of recombinant DNA technology?
Which of the following statements about gene therapy are true?

Practise this topic for free