CLONING(human cloning)

CLONING

In biology, cloning is the process of producing similar

populations of genetically identical individuals that

occurs in nature when organisms such

as bacteria, insects or plants reproduce asexually.

Human cloning is the creation of a genetically identical

copy of a human. The term is generally used to refer to

artificial human. Human cloning which is the

reproduction of human cells and tissue.

History of cloning

1953 Structure of DNA discovered

1993 Human embryos were first cloned (artificial embryo)

July 5, 1996 Dolly was born, Organization: Roslin Institute at UK

Dolly – the first mammal cloned using mature cell

Dolly the Lamb in 1996

Method: Nuclear transfer

Organization: RoslinInstitute at UK and PPL Therapeutics

Photo from Ming Pao 18th August 2002

Example of cloning

Cumulina the Mouse in

1998

Organization:

University of Hawaii

Photo from Ming Pao 28th December 2002

Example of cloning

Cattle in 1998

Organization:

Kinki University at

Japan

Photo from Ming Pao 28th December 2002

Example of cloning

Generation of Prometea, 2003

Organization: A research laboratory in

Italy

Photo from Nature No.6949

Definition and typesCloning is the production of 1 or more individual

plants or animals (whole or in part) that are genetically identical to an original plant or animal.

I’ll discuss two types:

(1) Reproductive cloning (adult DNA cloning)would be using cells to create cloned humans.

(2) Therapeutic cloning (biomedical cloning) is the use of (stem) cells for medicinal or research purposes.

Reproductive cloning

Produces a duplicate of an existing animal

Dolly

DNA from an ovum removed and replaced with the DNA from a cell removed from an adult animal

The fertilized ovum (called a pre-embryo) implanted in a womb and allowed to develop into a new animal

Very controversial: banned in many countries

Fuse Cell and

enucleated egg with

electricity.

Egg is fused with Cell

Therapeutic cloning

Initial stages identical to reproductive cloning

However, stem cells are removed from the pre-embryo to

produce tissue for a whole organ for transplant back into

the person who supplied the DNA

Therapeutic Cloning

1. Nucleus of an egg cell is

replaced with the nucleus of a

body cell.

2. Egg cell is stimulated with

electricity.

3. Embryo grows.

4. Embryo stem cells are

collected and used to treat

the donor.

Therapeutic Cloning 2

What are the risks of cloning?

• Reproductive cloning is expensive and highly inefficient

• Cloned animals tend to have more compromised immune

function and higher rates of infection, tumor growth, and

other disorders

• Genomes of cloned mice are compromised, 4% of genes

function abnormally

• A process called "imprinting" chemically marks the DNA from

the mother and father so that only one copy of a gene (either

the maternal or paternal gene) is turned on. Defects in the

genetic imprint of DNA from a single donor cell may lead to

some of the developmental abnormalities of cloned embryos.

Psychological Effects - Identity

and Relationship

Would the clone feel that he or she was just a copy of someone else who's already existed and not really themselves?

What will be my relationship to the one I was cloned from?

No one can predict with any degree of assurance what the response would be.

Is adult human DNA cloning

moral?

Some talents seem to be genetically influenced, ability seems to run in

families. Cloning using the DNA from the cell of an adult with the desired

traits or talents might produce an infant with similar potential.

Yes

?

Two lesbians could elect to have a child by adult

DNA cloning rather than by artificial insemination

by a man's sperm. Each would then contribute

part of her body to the fertilized ovum: one

woman would donate the ovum, which contains

some genetic material in its mitochondria; the

other woman the nuclear genetic material. Both

would have parts of their bodies involved in the

conception. They might find this more satisfactory

than in-vitro fertilization using a man's sperm

Yes

?

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