CLONINGAMIRA ZULAIKHA

065NUR AMALINA 067

OBJECTIVES

• What is cloning?• Purposes• Types of cloning• Risks

Cloning

• The term clone is derived from the ancient Greek word κλών (klōn, “twig”), referring to the process whereby a new plant can be created from a twig

• Production of many identical copies of a molecule

• Exact genetic copy of another, every single bit of DNA is the same between the two

Cloning animal models of disease

Cloning for medical purposes

PURPOSES

TYPES OF CLONING

Gene Cloning

Reproductive

CloningEmbryo Cloning

Tissue Cloning

Gene Cloning

• DNA cloning or recombinant DNA technology• Process of transferring of a specific DNA fragment on

one organism to a self-replicating genetic component of the cloning vector such as bacterial plasmid

• Following transfer of DNA fragment, the molecule is propagated in the host organism

• Used widely in genetic engineering for sequencing genomes and gene therapy

Reproductive Cloning

• To produce an animal having the same nuclear DNA from the existing animal

• Uses the principle of somatic cell nuclear transfer (in which genetic material from the donor cell is transferred to an egg from which the genetic material has been removed)

• Allowed to divide by chemicals or electric current• The cloned embryo is then transferred to the uterus of the host

female where it grows into a complete fetus • Dolly sheep is the first cloned animal (Roslin Institute, Edinburgh,

Scotland, 1997)

Embryo Cloning

• Also called therapeutic cloning which refers to the production of human embryos for research purposes

• To yield stem cells to study human evolution and disease treatments

• Stem cells are extracted in the blastocyst stage of development, which can practically generate any type of cells in the human body

• Stem cells are used to replace degenerating cells• In Alzheimer’s disease, cancer etc.

Tissue Cloning

• Called tissue culture• Cells are allowed to grow in a suitable medium• The cloned cells are used to study the action of

hormones, antibiotics and pharmaceutical products

Risks of Cloning• High failure ratei) The enucleated egg and the transferred nucleus may not be compatibleii) An egg with a newly transferred nucleus may not begin to divide or

develop properlyiii) Implantation of the embryo into the surrogate mother might failiv) The pregnancy itself might fail

• Problems during later development (LOS)

• Abnormal gene expression patterns

References

• GK Pal, Textbook of Medical Physiology, 2nd Edition, Ahuja Publishing House