Gene-Transfer-Techniques-in-Genetic-Engineering chapter-5.pptx

Gene transfer

1. Chapter 5 Gene Transfer Techniques in Genetic Engineering Gene transfer techniques are essential tools in genetic engineering used to manipulate an organism's genetic material. These techniques allow scientists to Introduce, delete, or alter specific genes in an organism's genome, Enabling them to study gene functions, develop genetically modified organisms (GMOs), and Generate valuable products.

2. Transformation Transformation is a commonly used technique to introduce foreign DNA into bacteria . In transformation, foreign DNA is introduced into a host cell, leading to stable incorporation into its genome. Commonly used in bacteria. Cells that have successfully taken up the foreign DNA can be selectively grown and studied further . The process involves a series of steps, including isolation of plasmid DNA, digestion with restriction enzymes, ligation , and introduction of the recombinant plasmid into host bacteria. Results and Applications Successful transformation can be confirmed by the growth of bacterial colonies on selective media. This technique is essential in genetic engineering research and biotechnology applications.

3. Transduction Transduction involves the transfer of genes between cells via a viral vector . The virus acts as a carrier for the foreign DNA, which gets inserted into the host cell's genome. This technique is commonly used in both bacterial and eukaryotic cells . Different types of viruses such as bacteriophages or retroviruses, can be used as vectors depending on the target organism . Conjugation Conjugation is a process of gene transfer in bacteria, where plasmids containing specific genes are directly transferred from one bacterial cell to another . It involves the physical connection of two cells through a conjugation bridge, allowing the transfer of genetic material. This technique can lead to the rapid spread of genes, such as antibiotic resistance genes, among bacteria.

4. Viral Vectors Viral vectors are commonly used vehicles to deliver genes into target cells. They mimic the natural infection process of viruses and facilitate gene transfer with high efficiency . There are several types of viral vectors, including retroviruses, adenoviruses, lentiviruses, and adeno-associated viruses. Each type has its unique strengths and limitations. Viral vectors have revolutionized gene therapy, allowing the treatment of genetic diseases by replacing or correcting faulty genes. They also play a crucial role in vaccine development and cancer research . Types Applications

5. Electroporation Electroporation involves exposing cells to brief electric shock , which creates temporary pores in the cell membrane. This facilitates the uptake of foreign DNA and allows gene transfer . Electroporation is a versatile technique suitable for various cell types, including bacteria, yeast, plant cells, and mammalian cells. It offers high efficiency and allows for precise control. Applications Electroporation is widely used in research laboratories for genetic engineering, gene therapy, and the creation of transgenic organisms . It has also shown promise in medical treatments like cancer immunotherapy .

6. Gene Gun The gene gun, also known as biolistics, is a technique that uses microscopic particles coated with DNA to deliver genes into cells . It provides a physical method of gene transfer. Procedure The process involves loading DNA-coated particles onto microscopic gold beads or tungsten discs and shooting them into the target cells using a specialized machine called a gene gun. Applications Gene guns are widely used in plant genetic engineering, enabling the introduction of desirable traits, such as pest resistance or increased yield . They are also utilized in vaccine development and gene therapy research.

7. Transfection Transfection is a technique used to introduce foreign DNA or RNA into eukaryotic cells. It allows researchers to study gene expression, protein function, and cellular processes . Methods Transfection methods, including chemical-based approaches, such as calcium phosphate precipitation and lipid-mediated transfection, as well as physical methods like electroporation. Applications Transfection is instrumental in basic research, drug discovery, and biotechnology . It enables the production of recombinant proteins, the study of disease mechanisms, and the development of new therapeutic strategies.

8. DNA Microinjection DNA microinjection involves using a fine glass pipette to inject DNA directly into the nucleus of a cell . The procedure involves the direct injection of the DNA into the nucleus of the host cell with the help of a glass microinjection tube or syringe (foreign DNA into Cell, Egg, oocyte, embryos of animals ) DNA microinjection offers high precision and control over the gene delivery process. It is widely used in genetic engineering, embryology, and the creation of transgenic animals . Applications The technique has been instrumental in studying gene function, creating genetically modified organisms, and understanding developmental processes. It has also been used in gene therapy trials.

9. Microinjection of a Human Egg

10. In-direct Methods (Agrobacterium tumefaciens (Ti plasmid) This method uses Agrobacterium tumefaciens for the plant transformation experiments. This bacterium have natural ability to transfer DNA of their plasmids into plant genome upon infection of cells at the wound site and cause an unorganized growth of a cell mass known as crown gall .

11. This “crown gall disease” affects broad-leafed plants such as fruit trees, grapes, and ornamental plants. Wounded plants secrete a high content of phenolic compounds which serve as chemical attractants for Agrobacteria and stimulate expression of vir genes . It results in infection of plant by Agrobacterium, insertion of T-DNA region at a random site in host genome and proliferation of plant cells to form crown gall growth. The plasmid that was responsible for the tumor was named Ti ( tumour inducing ) plasmid or T-DNA.

12. Applications of Gene Transfer Techniques Gene transfer techniques have numerous applications in biotechnology, medicine, and agriculture: Biotechnology: Gene transfer techniques are used to produce recombinant proteins in bacteria or other organisms, leading to the production of pharmaceuticals, enzymes, and industrial chemicals. Medicine: Gene therapy involves the transfer of genes into patients with genetic disorders or acquired diseases to correct or replace faulty genes. Agriculture: Gene transfer allows the development of genetically modified crops with improved traits, such as increased yield, disease resistance, or nutritional value.

13. End of chapter five