30-07-2012, 03:20 PM
GENETIC ENGINEERING
GENETIC ENGINEERING.pptx (Size: 1.2 MB / Downloads: 34)
MEANING
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest.
GENETICALLY ENGINEERED ORGANISMS
An organism that is generated through the introduction of recombinant DNA is considered to be a genetically modified organism. The first organisms genetically engineered were bacteria in 1973 and then mice in 1974.
HISTORY
Genetic engineering as the direct manipulation of DNA by humans outside breeding and mutations has only existed since the 1970s. The term "genetic engineering" was first coined by Jack Williamson
Isolating the gene
First, the gene to be inserted into the genetically modified organism must be chosen and isolated. This typically involves multiplying the gene using polymerase chain reaction (PCR). If the chosen gene or the donor organism's genome has been well studied it may be present in a genetic library. If the DNA sequence is known, but no copies of the gene are available, it can be artificially synthesized. Once isolated, the gene is inserted into a bacterial plasmid.
Constructs
The gene to be inserted into the genetically modified organism must be combined with other genetic elements in order for it to work properly.
Gene targeting
The most common form of genetic engineering involves inserting new genetic material randomly within the host genome. techniques allow new genetic material to be inserted at a specific location in the host genome or generate mutations at desired genomic loci capable ofknocking out endogenous genes.
Transformation
DNA is generally inserted into animal cells using microinjection, where it can be injected through the cells nuclear envelopedirectly into the nucleus or through the use of viral vectors. In plants the DNA is generally inserted using Agrobacterium-mediated recombination
Selection
Not all the organism's cells will be transformed with the new genetic material; in most cases a selectable marker is used to differentiate transformed from untransformed cells.
Regeneration
As often only a single cell is transformed with genetic material the organism must be regrown from that single cell. In plants this is accomplished through the use of tissue culture. In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells. When the offspring is produced they can be screened for the presence of the gene
Confirmation
The finding that a recombinant organism contains the inserted genes is not usually sufficient to ensure that the genes will be expressed in an appropriate manner in the intended tissues of the recombinant organism.
GENETIC ENGINEERING.pptx (Size: 1.2 MB / Downloads: 34)
MEANING
Genetic engineering, also called genetic modification, is the direct human manipulation of an organism's genome using modern DNA technology. It involves the introduction of foreign DNA or synthetic genes into the organism of interest.
GENETICALLY ENGINEERED ORGANISMS
An organism that is generated through the introduction of recombinant DNA is considered to be a genetically modified organism. The first organisms genetically engineered were bacteria in 1973 and then mice in 1974.
HISTORY
Genetic engineering as the direct manipulation of DNA by humans outside breeding and mutations has only existed since the 1970s. The term "genetic engineering" was first coined by Jack Williamson
Isolating the gene
First, the gene to be inserted into the genetically modified organism must be chosen and isolated. This typically involves multiplying the gene using polymerase chain reaction (PCR). If the chosen gene or the donor organism's genome has been well studied it may be present in a genetic library. If the DNA sequence is known, but no copies of the gene are available, it can be artificially synthesized. Once isolated, the gene is inserted into a bacterial plasmid.
Constructs
The gene to be inserted into the genetically modified organism must be combined with other genetic elements in order for it to work properly.
Gene targeting
The most common form of genetic engineering involves inserting new genetic material randomly within the host genome. techniques allow new genetic material to be inserted at a specific location in the host genome or generate mutations at desired genomic loci capable ofknocking out endogenous genes.
Transformation
DNA is generally inserted into animal cells using microinjection, where it can be injected through the cells nuclear envelopedirectly into the nucleus or through the use of viral vectors. In plants the DNA is generally inserted using Agrobacterium-mediated recombination
Selection
Not all the organism's cells will be transformed with the new genetic material; in most cases a selectable marker is used to differentiate transformed from untransformed cells.
Regeneration
As often only a single cell is transformed with genetic material the organism must be regrown from that single cell. In plants this is accomplished through the use of tissue culture. In animals it is necessary to ensure that the inserted DNA is present in the embryonic stem cells. When the offspring is produced they can be screened for the presence of the gene
Confirmation
The finding that a recombinant organism contains the inserted genes is not usually sufficient to ensure that the genes will be expressed in an appropriate manner in the intended tissues of the recombinant organism.