Genetically Modified Organisms (GMOs)
In genetic engineering, the methods of gene transfer lead to the
production of transgenic animals and plants. These are called genetically
modified organisms. Transgenism has been recognized as one of the thrust
areas of biotechnology. (Transgenic organisms)
Gene transfer Methods
The uptake of genes by the cells in animals is called trans fection.
The transfected cells are used for a variety of purposes such as 1. The
production of chemicals and pharmaceutical drugs, 2. Study of structure and
function of genes and 3. Production of transgenic animals of
commercial value such as livestock animals and fishes. It is also called
molecular farming. In transfection, fertilized eggs/embryos or the cultured
cells are employed. (Transgenic organisms)
Transfer of genes to Fertilized eggs or embryos
The transfection of fertilized egg involves either the transfer of whole
nuclei or whole chromosomes; or their fragments or the DNA
segments. (Transgenic organisms)
A. For the transfer of whole nuclei, the cells are treated with cytochalasin B
and enucleated. The enucleated cells are incubated with the desired
karyoplasts (nuclei) for induction in presence of polyethylene glycol (PEG).
B. For transfer of whole chromosomes, metaphase cells are subjected to
hypotonic lysis and individual chromosomes or fragments are isolated and
then incubated with whole cells/eggs for transfection.
C. Microinjection of DNA segments : In this the fertilized eggs are injected
with DNA segments for integration. DNA integrated eggs are then used for
getting transgenic animals. D. Transfer of genes to cultured cells : In this stem cells are used. The stem cells are undifferentiated precursor cells. In these cultured cells, the gene can be delivered through vectors like retroviruses or directly by techniques such as microinjection using particle gun, electroporation or by the use of liposomes.
Transgenic animals have been produced in a variety of animals such
as mice, rabbits, sheeps, pigs, goats, cows, fishes etc.
Uses: (Transgenic organisms)
1. Transgenic animals are more efficient than their normal counterpart in feed
2. They exhibit faster growth and hence achieve the marketable size sooner.
3. Meat quality is good.
4. They are resistant to certain diseases.
5. They serve as bioreactors for obtaining valuable recombinant
proteins and pharmaceuticals from their milk or urine or blood.
Related Topics in Zoology:
- MODERN GENETICS Introduction and Scope
- Human Genetics – Karyotyping
- Karyotyping of Human chromosomes
- Genetic Engineering
- Tools Of Genetic Engineering
- Restriction enzymes – Recombinant DNA Technology
- DNA – Segmenting / Fragmenting
- Genetic Diseases
- Human Genome Project (HGP)
- Transgenic organisms
- Gene Therapy
- Scope of Genetic Engineering – Scope of Bioinformatics
- Genome sequencing
- Protein structure
UNIT 5. ENVIRONMENTAL SCIENCE Topic List Zoology
- Human population and explosion
- Population Explosion
- Growing Population and Environmental impacts
- Global warming – Green house effect
- Ozone layer depletion
- Prevention and Effect of Ozone depletions
- Waste management – Classification
- Management of hazardous wastes
- Management of non hazardous wastes
- Waste water treatment and management
- Conservation of Biodiversity
- Characteristics of a Bioreserve
- Energy crisis and its environmental impact
- Steps to be taken to resolve energy crisis
- Environmental impacts of Power Sources
- Poverty and environment
- Fresh water crisis and management
- Human population and explosion