CLONING Cloning Production of many identical copies of

CLONING

Cloning � Production of many identical copies of a molecule or population of genetically identical individual. � Clone � 4 – “trunk or branch” types ◦ Gene cloning ◦ Reproductive cloning ◦ Embryo cloning/ Therapeutic cloning ◦ Tissue cloning

Gene cloning � Also called DNA cloning or recombinant DNA technology � Widely used in genetic engineering for sequencing genome and gene therapy.

Recombinant DNA technology

Recombinant DNA technology � It is the ability to introduce genetic material into cells in such a way as to enable that DNA to replicate and be passed on to the progeny of cells. � It is also known by terms like genetic engineering, gene cloning, molecular cloning or gene manipulations. � In 1973, Boyer & Cohen introduced the desired genes of one organisms into another and cloned new genes.

Steps Involved � Step 1 Generation of DNA fragments and selection of desired segment of DNA – Restriction endonucleases. � Step 2 Selection of vectors/cloning vectors. � Step 3 Insertion of the selected DNA into cloning vector – DNA ligase.

� Step 4 Introduction of recombinant DNA into host cells. � Step 5 Propagation of recombinant DNA in the host cell. � Step 6 Selection of clones with recombinant molecules. � Step 7 Expression of the cloned gene in the host cell to produce our protein of interest.

Uses Of Recombinant DNA technology � Role of recombinant DNA technology in medicine. Diagnostic i. Diagnosis of infectious diseases – TB, AIDS, Malaria, chagas disease, etc. ii. Diagnosis of genetic diseases iii. Diagnosis of Alzheimer's disease §

Therapeutic Ø Gene therapy Process of inserting certain genes into the cell to treat diseases. § Disease Gene therapy Sickle cell anemia Beta globin Cystic fibrosis CFTR SCID Adenosine deaminase Hemophilia Factor IX Duchenne dystrophy Dystrophin

§ Role of recombinant DNA technology in pharmaceutical products � Human protein replacements � Vaccines � Therapeutic agents

Reproductive cloning � Used to produce an animal having same nuclear DNA from existing animal. � Uses somatic cell transfer principle. � In 1950 this was first carried out in frogs. � In 1997 Ian Wilmut -Dolly the sheep from nucleus of mammary epithelial cells that was transplanted into unfertilized egg. � Has been used to create variety of mammalians species. � 1 -3% success rate.

Cloning Dolly 1997 - 2003 (Roslin Institute http: //www. roslin. ac. uk/library/)

The Important Facts About Human Cloning 1. A clone would be a baby just like any other baby. 2. There is no important difference between a clone and an identical twin.

Embryo cloning � Also called therapeutic cloning. � Used to create stem cells to study evolution and disease treatments. � Stem cells are used to replace degenerating cells in Alzheimer's disease, cancer. � Transplanted cells are genetically identical to recipientbypasses immune system rejection.

Tissue cloning � Also called tissue culture. � Clone tissues used to study action of hormones, antibiotics and pharmaceutical products.

Ethical issue � Cloning of humans � Destruction of embryonic cells from which stem cells are produced. � Alleviated by –reprogramming somatic cells into pleuripotent state resembling embryonic stem cells

Potential uses of cloning � Replacing organs and other tissues Infertility � Replacing a lost child � Cloned animal for consumption � Gene therapy � Saving endangered species � Genome library �

DRAWBACKS Low success rate (Dolly took 276 attempts) � Tumours � Genetic defects � Over-growth syndrome � Pre-mature ageing (genetic age) � Massive quantities of human eggs required � Reduction in adaptability – genetic uniformity � Lack of knowledge

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