GENETIC ENGINEERING
GENETIC ENGINEERING
What is genetic engineering ?
It is about the tools & technologies of molecular biology for cleaving & rejoining DNA SEQUENCES from two or more different organisms.
These genetically modified DNA fragments are called as RECOMBINANT DNA molecules.
2. Application of DNA manipulation ranges from cloning genes to cloning organisms including transgenic microbes,important crops & farm animals.
3. We can get modified food products, human gene products, medical products.
4. Hereditary diseases can be cured.
5. In forensic investigations. DNA FINGERPRINTING is a reliable technique for forensic investigation.
These genetically modified DNA fragments are called as RECOMBINANT DNA molecules.
APPLICATIONS OF GENETIC ENGINEERING
1. These can be cloned & amplified virtually to unlimited extent.2. Application of DNA manipulation ranges from cloning genes to cloning organisms including transgenic microbes,important crops & farm animals.
3. We can get modified food products, human gene products, medical products.
4. Hereditary diseases can be cured.
5. In forensic investigations. DNA FINGERPRINTING is a reliable technique for forensic investigation.
Therefore GENETIC ENGINEERING is a kind of BIOTECHNOLOGY, alteration of genetic make up of cells by artificial means.
RECOMBINANT DNA
Transfer or replacement of GENES by artificial means to create the RECOMBINANT DNA.
HOW A RECOMBINANT DNA CREATED ?
By cutting DNA molecules at specific sites to get fragments of desired useful genes from one type of cell.These genes can be inserted into a convenient vector or carrier.These recombinant DNA can be put in another different cell of bacterium or plant or animal to get desirable species.
TOOLS OF GENETIC ENGINEERING
1. Isolate DNA from cell culture with desired gene, DNA segment can be excised by molecular scissors called as RESTRICTION ENZYMES.
2. These are synthesised by microbes are specific ENDONUCLEASE ENZYMES which can cleave double stranded DNA AT LIMITED SITES .
3. A vector is used as carrier for transferring selected DNA into cells.
4. A plasmid with small DNA from bacterium is good choice for indirect gene transfer as it can move from one cell to another & make several copies of itself.
5. Artificial chromosomes from bacteria & yeast called BACs & YACs. They are efficient for Eukaryotic gene transfer.
BACs are Bacteria Chromosomes.
YACs are Yeast Chromosomes.
Eukaryotic are multi cellular organism ex. Human Beings.
Prokaryotic are uni cellular organism ex. Amoeba
We require DNA synthesising enzymes such as DNA POLYMERASE to make the DNA Complimentary to the existing DNA. cDNA also known as Complimentary DNA.
DNA LIGASE IS AN ENZYME to join the DNA fragments by
PHOSPHODIESTER BOND.
From Fruit FLY to Elephant FRAGMENTS produced by RESTRICTED ENZYMES can be joined together.
STAGES OF GENE TRANSFER
BENEFITS OF RECOMBINANT DNA
Disease resistant, useful and better products as enzymes, hormones, vaccines with high skill.TOOLS OF GENETIC ENGINEERING
1. Isolate DNA from cell culture with desired gene, DNA segment can be excised by molecular scissors called as RESTRICTION ENZYMES.
2. These are synthesised by microbes are specific ENDONUCLEASE ENZYMES which can cleave double stranded DNA AT LIMITED SITES .
3. A vector is used as carrier for transferring selected DNA into cells.
4. A plasmid with small DNA from bacterium is good choice for indirect gene transfer as it can move from one cell to another & make several copies of itself.
5. Artificial chromosomes from bacteria & yeast called BACs & YACs. They are efficient for Eukaryotic gene transfer.
BACs are Bacteria Chromosomes.
YACs are Yeast Chromosomes.
Eukaryotic are multi cellular organism ex. Human Beings.
Prokaryotic are uni cellular organism ex. Amoeba
We require DNA synthesising enzymes such as DNA POLYMERASE to make the DNA Complimentary to the existing DNA. cDNA also known as Complimentary DNA.
DNA LIGASE IS AN ENZYME to join the DNA fragments by
PHOSPHODIESTER BOND.
From Fruit FLY to Elephant FRAGMENTS produced by RESTRICTED ENZYMES can be joined together.
STAGES OF GENE TRANSFER
1. Isolate a useful DNA segment from donor organism.
2. Splicing it into suitable vector so that each vector receives no more than one DNA fragment or gene to create a recombinant DNA.
3.To produce multiple copies of recombinant DNA
4. Insert altered DNA into recipient organism.
5. Screening of the transformed cells.
EXAMPLE OF RECOMBINANT DNA TECHNOLOGY
Ti [TUMORINDUCING]PLASMID occurs in soil bacterium AGROBACTERIUM TUMEFACIANS
HOW Ti [TUMORINDUCING]PLASMID WORKS ?
1. AGROBACTERIUM carries the TI PLASMID.
2. AGROBACTERIUM infect all agriculture crops like Soya bean, Tomato, Sunflower and NOT CEREALS WHICH LEAD TO CANCEROUS GROWTH called CROWN GALL TUMOUR.
3. PART OF TI PLASMID is transferred into Plant DNA called T DNA.
4. T DNA with Desired DNA is inserted into Chromosome of Host Plant. Now it multiplies but no longer produces Tumor.
5. Such plant cells will be cultured now, induced to multiply and make new category of Plants.
EXAMPLE OF RECOMBINANT DNA TECHNOLOGY
Ti [TUMORINDUCING]PLASMID occurs in soil bacterium AGROBACTERIUM TUMEFACIANS
HOW Ti [TUMORINDUCING]PLASMID WORKS ?
1. AGROBACTERIUM carries the TI PLASMID.
2. AGROBACTERIUM infect all agriculture crops like Soya bean, Tomato, Sunflower and NOT CEREALS WHICH LEAD TO CANCEROUS GROWTH called CROWN GALL TUMOUR.
3. PART OF TI PLASMID is transferred into Plant DNA called T DNA.
4. T DNA with Desired DNA is inserted into Chromosome of Host Plant. Now it multiplies but no longer produces Tumor.
5. Such plant cells will be cultured now, induced to multiply and make new category of Plants.
VECTORLESS DIRECT GENE TRANSFER
This is new technology like GENE GUN is used for direct gene transfer.
DNA coated onto microscopic pellets is shot into target cells.This technique is used successfully to insert genes which promote tissue repair into cells near wounds therefore reduce the healing time.
DNA coated onto microscopic pellets is shot into target cells.This technique is used successfully to insert genes which promote tissue repair into cells near wounds therefore reduce the healing time.
APPLICATIONS OF RECOMBINANT DNA TECHNOLOGY -
1. It can be used to elucidate molecular events in biological process like CELULLAR DIFFRENTIATION & AGEING.It can be used for making gene maps with precision.It is also used to know the complete nucleotide sequence of genome of various organisms.
2. In pharmaceutical & biochemical industry useful chemical compounds can be produced cheaply & efficiently like HEPATITIS B VACCINE; EDIBLE VACCINE.
3. This technology also provide many tools to diagnose diseases like construction of probes;short segments of single stranded DNA attached to radioactive marker.Now these are used for identification of infectious agents Ex-FOOD POISONING SALMONELLA,HEPATITIS VIRUS , HIV & so on.
2. In pharmaceutical & biochemical industry useful chemical compounds can be produced cheaply & efficiently like HEPATITIS B VACCINE; EDIBLE VACCINE.
3. This technology also provide many tools to diagnose diseases like construction of probes;short segments of single stranded DNA attached to radioactive marker.Now these are used for identification of infectious agents Ex-FOOD POISONING SALMONELLA,HEPATITIS VIRUS , HIV & so on.
GENE THERAPY
IN GENETIC ENGINEERING.GENE THERAPY in humans is to replace “A FAULTY GENE” by normal healthy functional gene.
Rare genetic diseases like SICKLE CELL ANAEMIA caused by MUTATION in gene A KILLER DISEASE SCID [severe combined immuno-deficiency] caused by defect in gene for ADENOSINE DEAMINASE [ADA].These patients have no functional T-LYMPHOCYTES THEREFORE WEEK IMMUNE SYSTEM.
1 LYMPHOCYTES a kind of white blood cells extracted from bone marrow of patient SCID.
2 Good copy of human gene encoding this enzyme is introduced into these cells. Special viruses called RETROVIRUSES act as VECTOR.
3. This vector incorporate the ADA gene
Rare genetic diseases like SICKLE CELL ANAEMIA caused by MUTATION in gene A KILLER DISEASE SCID [severe combined immuno-deficiency] caused by defect in gene for ADENOSINE DEAMINASE [ADA].These patients have no functional T-LYMPHOCYTES THEREFORE WEEK IMMUNE SYSTEM.
1 LYMPHOCYTES a kind of white blood cells extracted from bone marrow of patient SCID.
2 Good copy of human gene encoding this enzyme is introduced into these cells. Special viruses called RETROVIRUSES act as VECTOR.
3. This vector incorporate the ADA gene
which has packing sequence but no viral genes.
4. Infectious bone marrow stem cells removed from patient SCID with vector & helper virus produces new virus particles with ADA gene inserted.
5.These cells have good copy of gene in addition existing faulty copy.
6.Treated cells re injected to patient”s bone marrow.
7. These cells have fully functional ADA gene.These are normal in immune system.
This approach is used to introduce THERAPEUTIC genes into particular tissues work throughout life.
CLONING
It means CARBON COPY exact copy of single parent.It is meant for living species.
They have identical genetic make up sometime genetic variation.
MICROBES & PLANTS reproduce asexually produce clones. MONOZYGOTIC CLONES re IDENTICAL TWINS.These are started as single cell in mother's womb fertilized egg divides into two each cell developed into a separate twin having same genetic make up DOLLY A SHEEP is first clone in world.
They have identical genetic make up sometime genetic variation.
MICROBES & PLANTS reproduce asexually produce clones. MONOZYGOTIC CLONES re IDENTICAL TWINS.These are started as single cell in mother's womb fertilized egg divides into two each cell developed into a separate twin having same genetic make up DOLLY A SHEEP is first clone in world.
CLONING is to produce many identical organisms.
1. MICROBIAL CLONING Microbial cell can be duplicated every time it divides. Many improved genetically altered strains of microorganisms can be cloned
1. MICROBIAL CLONING Microbial cell can be duplicated every time it divides. Many improved genetically altered strains of microorganisms can be cloned
2. CELL CLONING-TOTIPOTENCY - It is potential ability of plant cell to grow into a complete plant.
PLURIOPOTENCY- It is a potential ability of cell to develop any type of cell in animal body. Ex nerve cell or kidney cell.
PLURIOPOTENCY- It is a potential ability of cell to develop any type of cell in animal body. Ex nerve cell or kidney cell.
3. PLANT CLONING-Many beautiful flowers are from cloned plants as orchids. It is very useful in agriculture to get the disease, drought,insect, pest resistant VITMODIFIED FOOD[GMF] like VIT-A rich rice & LYSINE-rich pulse seeds are produced.
4. ANIMAL CLONING - It is a difficult process then plant cloning.This is because animal cells lose their TOTIPOTENCY on reaching gastrula stage of development.A somatic cell is stored under nutrient deprived culture also called udder cell.Now they do not divide.Their active genes are switched off.One complete udder cell with nucleus selected as nucleus carries the mother’s genetic information. An unfertilised egg cell from different sheep .Its nucleus sucked out leaving empty cell.Now this cell is fused with udder cell nucleus. It has now mother’s nucleus.Altered egg was cultured for six days.many embryos produced.One implanted in uterus of surrogate mother.Then it grows as normal
In JAPAN eight identical calves from one fertilised cell of their mother produced.
TRANGENICS OR GENETICALLY MODIFIED ORGANISMS [GMOs]
We can produce transgenic crops with useful characters .They can created by incorporating into their genetic make up foreign genes or cloned genes.Ex-gene coding for insecticidal protein from BACILLUS transferred to cotton plant.It became resistant to BOLLWORM. The transgenic GMO tomato called Flavr savr has long life & flavourful. Transgenic animals are more healthy, cattle with increased milk production & human protein.Transgenic pigs have human genes their organs can be transplanted in humans like heart , kidney, pancreas etc.
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