Genetic Engineering, stem cells and Cloning

WHAT DOES GENETIC ENGINEERING MEAN?

-The simple addition, deletion, or manipulation of a single trait in an organism to create a desired change

-A technology used to order the genetic material of living cells in order to produce new substance or perform

new functions.

-It is used by scientists to change the DNA of living organisms .

WHAT IS THE DANGER OF GENETIC ENGINEERING?

Imprecise technology :

-A genetic engineer moves genes blindly from one organism to another .

-Genetic engineering is like performing heart surgery with a shovel.

Side effects :

-Some scientists believe that introducing genetically modified genes may have an irreversible effect with consequences yet unknown.

What are Stem Cells?Stem Cells are extraordinary because::

They can divide and make identical copies of themselves over and over again (Self-Renewal)

They can remain Unspecialized with no ‘specific’ function. . . .

or they become Specialized (Differentiated) with the potential to produce over 200 different types of cells in the body.

Description: A colony of embryonic stem cells. 10X. Image in the Public Domain.

Description: (A) Human ESCs; (B) Neurons derived from Human ESCs. Images courtesy of Nissim Benvenisty.

The Major Types of Stem Cells

A. Embryonic Stem Cells_ From blastocysts left over from In-Vitro Fertilization in the laboratoryFrom aborted fetuses (or foetuses)

B. Adult Stem CellsStem cells have been found in the blood, bone marrow, liver, kidney, cornea, dental pulp, umbilical cord, brain, skin, muscle, salivary

gland. . . .

Advantages and Disadvantages to Embryonic and Adult Stem Cells.

Embryonic S.C.Adult S.C.“Pluripotent”

(can become any cell)“Multipotent”

“(can become many but not any)”

Stable. Can undergo many cell divisions.

Less Stable. Capacity for self-renewal is

limited.

Easy to obtain but blastocyst is destroyed

Difficult to isolate in adult tissue.

Possibility of rejection ??Host rejection minimized

Why is Stem Cell Research So Important to All of Us?

-Stem cells allow us to study how organisms grow and develop over time.

-Stem cells can replace diseased or damaged cells that can not heal or renew themselves.

-We can test different substances (drugs and chemicals) on stem cells.

-We can get a better understanding of our “genetic machinery”.

What Human Diseases are Currently Being Treated with Stem Cells?

-Parkinson’s Disease-Leukemia (Bone Marrow Transplants)

-Skin Grafts resulting from severe burns

Stem Cell Therapy has the Potential to:

-Regenerate tissues/organs-Cure diseases like diabetes, multiple

sclerosis, etc.

WHAT DOES CLONING MEAN?

-A clone is a group of cells or organisms which are genetically identical and have all been produced from the same original cell .

-There are three main types of cloning , two of which aim to produce alive cloned offspring and one which simply aims to produce stem cells and then human organs.

Types of Cloning

1.Adult cell or reproductive cloning

2 .Embryo cloning

3 .Therapeutic or biomedical cloning

Adult cell or reproductive cloning

-This is the technology which resulted in Dolly the sheep .

-This form of cloning involves taking a cell from an adult animal and producing a new, identical individual .

-The process is very complex, involving three different females and several different stages.

Reproductive cloning

egg

take the nucleus (containing DNA)

remove nucleus and take the

rest of the cell

adult cell

Cloneidentical to the individual

that gave the nucleus

Dolly the sheep

Embryo cloning-Embryo cloning is a relatively new technique. It is

used with embryos from the best animals avaliable, or from genetically engineered embryos which are capable of producing human medicines in their milk. It is a big step on from embryo transfer.

-In embryo transfer the best animals are stimulated by hormones to release many fertile eggs at the same time. The eggs are fertilised and the early embryos are then flushed out of the uterus of the biological mother and transplanted into a number of surrogate mothers. Using this technique, some cows have produced fifty calves a year!

Therapeutic or Biomedical Cloning

-Therapeutic cloning involves using cells from an individual to produce a cloned early embryo which is then used as a source of embryonic stem cells .

-The hope instead is to produce pluripotent stem cells which can in turn develop into new tissues or organs for people who are seriously ill.

WHAT IS THE DANGER OF CLONING?

-Scientists said cloning techniques are still too underdeveloped to attempt on

humans .-Experience with animals has shown

that most clone pregnancies fail, or result in offspring being delivered dead or deformed.

-Those clones that are born, live fewer years than they are supposed to and some aspects of their body systems

don’t work well in the long term.

QUESTIONS TO DISCUSS

Does genetic engineering harm or benefit human society.?

What are the dangers of genetically engineered foods or why would it be a

benefit for the world.?

How can cloning help or hurt farmers.?

Why would farmers, doctors and manufactures be interested in genetic engineering.?

Is genetic engineering the best solution.?

What is your personal opinion regarding genetic engineering and human cloning.?

Why the Controversy Over Stem cells?

-Embryonic Stem cells are derived from extra blastocysts that would otherwise be discarded following In-Vitro Fertilization.

-Extracting stem cells destroys the developing blastocyst (embryo).

-Questions for Consideration-

1 .Is an embryo a person?2 .Is it morally acceptable to use

embryos for research?

3 .When do we become “human beings”?