MAMMALIAN CLONING, EMBYO

STEM CELL TECHNOLOGIES AND ETHICAL

ISSUES OF HUMAN CLONING.

BY DR.MADINA SIDDIQUE.

The technology of nuclear transfer into enucleated oocytes (cytoplasms) was already successfully used in 1987 for reproduction of live bovine and murine offsprings however the embryo development could then be obtained when transplanted nucleus originated from blastomeres,i.e cells from the first divisions ofpreimplantation embryo development .The birth in 1997 the first sheep cloned from an adult mammary glands cells that conveyed the full impact of the potential of reproductive cloning since now it could be done at any time during the life of anindividual being.

REPRODUCTIVE CLONING

GENE/DNA CLONING

GENE CLONING• Gene cloning is the process in which a gene of interest

is located and copied (cloned) out of DNA extracted from an organism. When DNA is extracted from an organism, all of its genes are extracted at one time. This DNA, which contains thousands of different genes. The genetic engineer must find the one specific gene that encodes the specific protein of interest.

• The term genomic DNA clone or chromosomal DNA clone then refers to an individual cell carrying a cloning vector wit

• h one of the cellular DNA fragments.

WHAT IS GENE CLONING?

WHY WE CLONED DNA?

THE BASICS OF CLONING

• Source of DNA: to be cloned• Choice of vectors: to carry,maintain,and

replicate cloned gene in hpost cell• Restriction enzyme:to cut dna• DNA ligase:to join foreign and vector DNA___

recombinant DNA• Host cell: in which the recombinant DNA can

replicate.

HOW IS DNA CLONED?

Cell Based DNA Cloning Cell Free DNA Cloning

CELL BASED DNA CLONING• DNA is extracted here from blood.• Restriction enzyme eg:Ecor1,Hind3 etc cut the

DNA into small pieces.• Different DNA pieces cut with the same enzyme

can join or recombine.

CELL FREE DNA CLONING• Developed in mid 1980’s• Nobel prize was given to Kary Mullis in 1993• DNA fragments can be amplified in large

amounts• In vitro technique

THERAPEUTIC CLONING Cloning designed as therapy for a disease. In

therapeutic cloning, the nucleus of a cell, typically a skin cell, is inserted into a fertilized egg whose

nucleus has been removed. The nucleated egg begins to divide repeatedly to form a blastocyst.

How is Therapeutic Cloning Performed?

Therapeutic cloning is another phrase for a procedure known as somatic cell nuclear

transfer (SCNT). Here's how it works: A scientist extracts the nucleus from an

egg The nucleus holds the genetic material for

a human or laboratory animal The scientist then takes a somatic cell,

which is any body cell other than an egg or sperm, and also extract the nucleus from

this cell

The nucleus that is extracted from the somatic cell in the patient is then inserted

into the egg, which had its nucleus previously removed

In a very basic sense, it's a procedure of substitution. The egg now contains the

patient's genetic material, or instructions It is stimulated to divide and shortly

thereafter forms a cluster of cells known as a blastocyst

Benefits of Therapeutic Cloning

• Organ transplant alternative• Leukemea• Generative diseases• Spinal cord repair• Skin grafting

Embryonic Stem Cells For

Therapeutic Cloning

My personal beliefs – not necessarily yours!

• Using embryonic stem cells from aborted fetuses is morally reprehensible to a large enough fraction of society that it should never become the source of choice for human stem cells.

• Embryonic stem cells will be only a temporary, but unfortunately probably necessary, tool needed by researchers to learn how to modify adult stem cells (for which there is little controversy) for a similar use.

*But there are different types of embryonic stem cells, some of which are ethically less controversial than others.

Different kinds of stem cells

Embryonic stem cells come from embryos (<6 weeks). Stem cells from blastocysts (2 weeks) are virtually “immortal”.

Fetal stem cells come from fetuses (> 6 weeks)

Stem cells are present in some adult tissues, including brain, spinal cord, and bone marrow.

Embryonic Stem Cells

ES cells was demonstrated by formation of ectoderm,mesoderm and endoderm

Importance of Stem CellsStudies of human

embryonic stem cells will lead to major advances in human biology

Embryonic stem cell research will provide critical insights into mechanisms of cell differentiation, growth, and death.

•Human embryonic stem cell therapies can save lives and restore function of people

Human embryonic stem cell can replace damaged or lost cells

Understanding stem cells may provide keys to why people age.

Limitations on the study of human embryonic stem cell research will hold back biomedical research.

These conditions are the most common and costly causes of disability in the United States.

These include diabetes, degenerative neurological diseases, demyelinative diseases, brain & spinal cord injury.