Gene Cloning

A method of gene cloning includes the use of recombinant plasmids. This has been used in the production of insulin, production of vaccines and many more.

Social Reduced costs of therapeutics made with bacteria
Wider access to treatments
Employment opportunities in the biotech industry
Misuse for non-therapeutic purposes
Biological Human recombinant proteins more effective than proteins purified from other animals Risk of contamination by bacterial molecules
New, safer vaccines possible
Ethical Use of bacteria for therapeutics addresses philosophical, cultural or religious objections to animal use Manipulation or shifting of genes may be seen as unethical, regardless of purpose

DNA Probe

DNA probes are artificially created fragments of ssDNA and ssRNA which are labelled with a radioactive or fluorescent dye that bind to a specific sequence of DNA. Therefore, they are useful in determining if an individual is carrying a specific allele or has a specific sequence of DNA

DNA Profiling – RFLP

Restriction fragment length polymorphism is where a section of DNA is amplified with PCR, cut with restriction enzymes and then run through gel electrophoresis. The banding of the gel is analysed by comparing the similarities and differences in lengths of fragments to another sample. e.g. DNA from a suspect and from a crime scene.

Due to mutations and variation in alleles and changes in the DNA sequence, the recognition sites will vary and therefore, everyone will have different lengths of DNA fragments when cut with a restriction enzyme. RFLP analysis is generally not used anymore as STR analysis is both cheaper and faster

DNA Profiling – STRs

Short tandem repeats or microsatellites are short fragments of non-coding DNA which repeat many times and are highly variable, making them ideal for DNA profiling. These DNA sequences are unique to each person, and therefore by comparing number of repeats at several loci, one can identify a person relatively easily.

STRs analyses the number of repeating tandems of a 2-5 base pair sequence of DNA at multiple loci. The DNA is first amplified using PCR and then various alleles of each STR are then separated and made visible with fluorescent dyes. The resulting DNA profile is a series of coloured peaks at different locations, with each peak being one allele of one specific STR. The location of each peak indicates the size of the allele and hence the number of repeats.

DNA Databanks Debate about the balance between human rights and the protection of the community. For example, whose DNA profiles should be added to the national database? Individuals convicted of serious crimes or should all individuals convicted be included too? Or, should they be held in databanks permanently or should they be removed after a given period?
Familial Searching This is where investigators search for the relatives of a crime scene profile. This identifies a person not because of what they are known to have done, but because they have criminal relatives
Predicative Testing This is where a sample of a person’s DNA is used to predict aspects of that person’s phenotype. This reinforces the possibility of prejudices against certain groups within the community and promotes racial stereotypes. Furthermore, this is not a mature science, but still in development

Genetic Screening

Genetic screening is commonly used to achieve early detection or exclusion of inherited disorders. Its purpose is to essentially confirm or rule out the presence in a person of a defective allele that is involved in an inherited disorder or that increases the persons’ susceptibility to a disease.

Social Privacy, Reproductive decisions Storing people’s genetic information
Biological Accuracy, possible false positive and negatives Potential to correct mutations, Intervention in evolution
Ethical Informed consent for DNA sampling
Security of stored genetic data
Legal access to genetic information
Reliability of DNA as proof of guilt or innocence

Genetically Modified Organisms

GMOs are organisms whose genomes have been altered using genetic engineering technology. This is achieved by the addition or silencing of a gene or segment of DNA so that either function is gained or lost. To be identified as a GMO, the added or lost gene must be heritable

Transgenic Organisms

Transgenic organisms are those that contain foreign DNA from an unrelated species. These fragments of foreign DNA can be introduced via pronuclear microinjection, a retrovirus or electroporation.

Case Studies

GMO rice crops have been given genes which confer tolerance to environmental stress, e.g. drought, flood, salt tolerance, increasing the productivity of the rice plant. While transgenic rice plants e.g. golden rice, have a foreign gene that codes for β-carotene, attempting to aid those in impoverished nations where there was a lack of vitamin A

GMO Cotton plants have been modified to allow them to produce a natural insecticide, reducing the need to spray the plants with added chemicals. Insecticides can be toxic to people, but some naturally occurring toxins, e.g. those produced by the GMO cotton plants are not toxic to people

Social Increased food supply, nutritional content and food quality
Expanded range for growth of agricultural species
Labelling and consumer choice
Patents and pricing
Biological Safety of consuming GMOs
Cross pollination b/w GM plants and wild plants
Cross pollination b/w GM and non-GM crops
Viability of transgenic organisms in the wild
Health of GMOs
Genetic variation in agriculture
Ethical Violation of animal rights
Intervention in evolutionary process
Human self-interest overrides ethical
treatment of other organisms

Golden Rice