Table of contents |
|
What is Gene Transfer? |
|
Steps involved in Gene Transfer |
|
Methods for Gene Transfer |
|
Achievements of Genetic Engineering |
|
Gene transfer is a technique where new DNA is added to the cells of a living organism. This can be done by using carriers like plasmids or modified viruses. The new DNA can be added to the cells outside the organism and then put back into the organism, or it can be directly added to the cells inside the organism.
Types of Gene Transfer
The process of gene transfer can be summarized in four key steps:
(a) Isolation of gene and vector (by PCR)
(b) Digestion of gene and vector (by restriction endonuclease)
(c) Ligation of gene and vector (by DNA ligase)
(d) Selection and expression of transgenic construct
There are two methods of gene transfer:
Indirect or vector-mediated gene transfer in plants involves the use of a plasmid vector. One widely employed vector for plant transformation is the Ti-plasmid found in Agrobacterium tumefaciens.
Agrobacterium-mediated Gene Transfer
In the direct gene transfer methods, the foreign gene of interest is delivered into the host plant without the help of a vector. The following are some of the common methods of direct gene transfer in plants.
The various method of direct gene transfer is:
(i) Chemical method
Use chemicals like polyethylene glycol and polyvinyl alcohol to help plant cells take in foreign DNA.
Start with plant protoplasts (cells without cell walls) in a magnesium-rich medium.
Add plasmid DNA with the desired gene. Use polyethylene glycol, maintain pH at 8, and briefly heat protoplasts. Cool them on ice to boost DNA uptake.
Allow incubation for DNA integration. Later, reduce polyethylene glycol and increase calcium ions for better transformation efficiency.
(ii) Electroporation
A pulse of high voltage is applied to protoplasts, cells or tissues which makes transient pores in the plasma membrane through which uptake of foreign DNA occurs.
(iii) Biolistic gun
Foreign DNA is attached to tiny gold or tungsten particles, typically measuring 1-3 µm. These particles are then shot onto the target tissue or cells using a device known as a gene gun, micro projectile gun, or shotgun. After bombardment, the treated cells or tissues are grown in a specific medium to encourage the development of plants from the modified cells.Gene Gun
(iv) Microinjection
The DNA is directly injected into the nucleus using fine tipped glass needle or micro pipette to transform plant cells. The protoplasts are immobilised on a solid support (agarose on a microscopic slide) or held with a holding pipette under suction.
Microinjection
(v) Lipofection
Artificial phospholipid vesicles called liposomes are valuable for transferring genes. They enable the transfer of genes or DNA from the liposome into the vacuole of a plant.
DNA recombinant technology or genetic engineering provides great benefits for the advancement of science and society.
![]() |
Download the notes
Genetic Engineering Technique: Gene Transfer
|
Download as PDF |
Tobacco
Cry-protein
Application of Genetically Engineered Microbes
114 videos|429 docs|209 tests
|
1. What is gene transfer and why is it important in genetic engineering? | ![]() |
2. What are the main steps involved in the gene transfer process? | ![]() |
3. What methods are commonly used for gene transfer? | ![]() |
4. What are some significant achievements of genetic engineering through gene transfer? | ![]() |
5. How has gene transfer technology impacted agriculture and medicine? | ![]() |