When you think of god's creation, a thought may come that if it were in your hands to choose the characteristics of an organism. You would definitely not miss such a chance. Well, you can't do it at home! Many schools of thought had worked on it successfully.
What is transformation? : The uptake of DNA by the bacterial cells is called transformation. DNA is said to be the genetic material of living organisms. It determines the characteristics of an organism. DNA contains genes. Each gene is responsible for a single characteristic. Hence if the desired part of DNA is transformed into the bacterial cells, we get the organism with characteristic of our choice.
Transformation of individual cells:
With most organisms the main barrier to DNA uptake is the cell wall. The animal cells grown artificially in the lab, which usually lack cell walls, are easily transformed. Especially when the DNA is already precipitated onto the cell surface by calcium phosphate treatment.For other types of cells the answer to this is to remove the cell wall. Enzymes that degrade yeast, fungal and plant cell walls are available and under the right conditions intact protoplasts (cell without a cell wall) can be obtained. Protoplasts generally take up DNA quite readily, but transformation can be stimulated by special techniques.Electroporation: in this technique, the cells are subjected to a short electric pulse, thought to induce the transient formation of pores in the cell membrane, through which the DNA molecules are able to enter the cell. After transformation the protoplasts are washed to remove the degradative enzymes and the cell wall spontaneously re-forms.
Other two physical methods:
1. Microinjection: it makes use of a very fine pipette to inject DNA molecules directly into the nucleus of the cells to be transformed. This technique was initially applied for animal cells but has subsequently been successful with plant cells.
2. Bombardment:this technique involves bombardment of the cells with high velocity microprojectiles, usually particles of gold or tungsten that have been coated with DNA. These microprojectiles are fired at the cells from a particle gun. This unusual technique is termed as biolistics and has been used with a number of different cell types.
Transformation of whole organisms:
With animals and plants the desired product may not be transformed cells, but a transformed organism. Plants are relatively easy to regenerate from cultured cells, though problems have been experienced in developing regeneration procedures for monocotyledonous species such as cereals and grasses. A single transformed plant cell can therefore give rise to a transformed plant, which carries the cloned DNA in every cell, and passes the cloned DNA to its progeny following flowering and seed formation.
Animals of course, cannot be regenerated from cultured cells, so obtaining transformed animals require rather more subtle approach.
One technique with mammals such as mice is to remove fertilized eggs from the oviduct, to microinject DNA, and then to re-implant it into mother's reproductive tract.