Gene Technology

Objectives• Describe the steps in the production of bacteria

capable of synthesising human insulin• Describe how genetically modified bacteria can be

identified using antibiotic resistance genes• Explain why and how genes for enzymes that

produce flourescent or easily stained substances are now used instead of antibiotic resistance genes as markers in gene technology

• Explain why promoters need to be transferred along with desired genes in gene technology

Objectives• Outline the principles of electrophoresis as used in

genetic profiling and DNA sequencing• Describe the causes and outline the symptoms of

cystic fibrosis (CF) as an example of a recessive genetic condition

• Describe the progress towards successful gene therapy for CF

• Discuss the roles of genetic screening for genetic conditions and the need for genetic counselling

Gene Technology

It is a technology in which we can use knowledge and understanding of genes to change the way in which

cells behave.

An organism whose DNA is altered by gene technology is said to be

genetically modified.

Insulin Production

• Isolation of Human Gene• Preparation of Vector• Formation of Recombinant DNA• Identification and Cloning

Advantages of Using Genetically Engineered Human

Insulin• More rapid response• A shorter duration of response• Less chance of an immune response to the insulin

developing• Effective in people who have developed a tolerance

for animal-derived insulin• More acceptable to people who feel it I unethical to

use pig or cattle insulin

Identifying the Genetically Modified Bacteria

• Using antibiotic-resistance gene as markers

• Use of GTP (green fluorescent protein)

Benefits of Gene Technology

• Create GMOs for specific uses• Result is quicker than selective breeding• Makes it possible to transfer genes between

totally unrelated organisms• Products specific to human can be made• Gene therapy• Increase resistance of crops to herbicides or

pesticides• Used in food industry

Potential Hazards of Gene Technology

• GMOs are unnatural and intrinsically unsafe, in contrast to those produced using selective breeding

• May pose danger in the natural environment• Hence, requires proper containment• Creation of transgenic organisms and

“contamination” of the outside environment– Idea of “superweed” and “superbugs”

Social and Ethical Implications of Genetic

Engineering• Improvement in people’s standard of living• Discussion of whether genetic engineering is

acceptable or not

Polymerase Chain Reaction (PCR)

• Also known as DNA amplification• DNA number is increased for several use

Electrophoresis

• A technique that is used to separate DNA fragments of different sizes

• Used for genetic profiling (fingerprinting) and;• For investigating the sequence of bases in a

particular length of DNA

Gene therapy on CF

Involves introducing a “correct” allele into a person’s cells as a treatment for a genetic disease, in this case cystic fibrosis

Somatic and Germ Cell Therapy

The Genetic Counsellor• A couple may be referred by a doctor or by

themselves if:– Either of them has genetic disease in their family– They belong to a group that is known to have a

high risk of genetic disease– There is a history of recurrent miscarriages– Woman is over 38– As part of the management of a high-risk

pregnancy

Genetic Screening

• This is the analysis of a person’s DNA to check for the presence of a particular allele

Ethics of Genetic Screening