12th Zoology

Gene therapy

Gene therapy

The fact that genes can be cloned to several thousand copies through
genetic engineering has given rise to an entirely novel model of therapeutic
device viz., Gene therapy. Gene therapy involves the replacement of
corrective genes in place of defective genes in human. There are two types
of gene therapy. They are 1). Somatic cell gene therapy and 2). Germ line
cell gene therapy. Both may be employed for treating the inherited diseases.

In somatic cell gene therapy the patient’s cells are taken from blood or
bone marrow, or skin and brain, treated through genetic engineering and
then replaced to the patient. Somatic cells are non-reproductive cells. These
cells and their genes when corrected, the genetic changes will not be inherited
to their children. On the other hand, this type of treatment could cure diseases
caused by single gene mutations.In this therapy, retroviruses are employed
as carriers of the genes. Their genetic material, RNA is copied into DNA. To
produce effective vectors certain essential genes are spliced out from the viruses. This will render the virus harmless and allow space for the therapeutic
genes to be inserted. Hundreds of millions of copies of the genes are needed
for somatic cell gene therapy. To carry them, the vectors should also be
multiplied in equal numbers. Experimentally, such enormous copies of virus
vectors are made using helper virus. The integrated vector and the cloned
gene is used in somatic cell gene therapy. Somatic cell gene therapy has been
successful in animals, so far.

Germ line cell gene therapy

The gene therapy is extended to reproductive or germ line cells in
order to prevent the genetic defects being inherited to children. The
technique has been shown to work positively in animals. In this, DNA is
injected into the nuclei of single celled embryos of cows, mice and sheep.

The DNA may get integrated into the chromosomes. The intergrated DNA,
ie., the new genes can direct the synthesis of new proteins into animals which
develop from these embryos. Germ line therapy has already been incorporated
developed in human embryos. Genes are inherited likewise
through retroviral vectors into human germ cells. Germ line therapy in
human is feasible, at any time, since eggs, sperms and single celled
embryos can be collected and stored by deep freezing using liquid nitrogen.
In vitro fertilization also may favour the above therapy. However, the therapy
is still underway.


Related Topics in Zoology:

Bio Zoology All Important Topics

  1. MODERN GENETICS Introduction and Scope

  2. Human Genetics – Karyotyping

  3. Karyotyping of Human chromosomes

  4. Genetic Engineering

  5. Tools Of Genetic Engineering

  6. Restriction enzymes – Recombinant DNA Technology

  7. DNA – Segmenting / Fragmenting

  8. Genetic Diseases

  9. Human Genome Project (HGP)

  10. Cloning

  11. Transgenic organisms

  12. Gene Therapy

  13. Bioinformatics

  14. Scope of Genetic Engineering – Scope of Bioinformatics

  15. Database

  16. Genome sequencing

  17. Protein structure


    1. Human population and explosion

    2. Population Explosion

    3. Growing Population and Environmental impacts

    4. Global warming – Green house effect

    5. Ozone layer depletion

    6. Prevention and Effect of Ozone depletions

    7. Waste management – Classification

    8. Management of hazardous wastes

    9. Management of non hazardous wastes

    10. Waste water treatment and management

    11. Biodiversity

    12. Conservation of Biodiversity

    13. Characteristics of a Bioreserve

    14. Energy crisis and its environmental impact

    15. Steps to be taken to resolve energy crisis

    16. Environmental impacts of Power Sources

    17. Poverty and environment

    18. Fresh water crisis and management

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