BT11.03: Evaluate therapeutic vs.

reproductive cloning

Tuesday

What is an example of pharming?– A. Using transgenic animals to produce

substances used in medicine– B. Using viruses to transfer genetic

information– C. Improving livestock with transgenic

research– D. Using transgenic mice to study cancer, MS

and muscular dystrophy

History of cloning

Dolly the sheep – first cloned mammal in 1997***

Very few scientists believe human cloning (reproductive cloning) should be permitted

Most scientists in favor of therapeutic cloning ***– the procedure used to produce embryonic stem cells that theoretically can be used to treat diseases

What is a clone?

Clone = precise genetic copy Reproductive cloning is really somatic

cell nuclear transfer (SCNT) In therapeutic cloning, the embryo is

not placed in a surrogate, but rather, undergoes cell division in the lab until it reaches blastocyst stage

There is currently no evidence of successful human cloning in the world***

Obstacles to reproductive cloning using animals

Success rate very low Vast majority of problems occur

during fetal development Additional problems show up after

birth and years later “Large offspring syndrome” =

cloned newborns 20-30% larger than usual, making it hard to deliver unborn babies

Embryonic and adult stem cells

Adult stem cells Embryonic stem cells Stem cells are important to

medical researchers because they may be used to create perfectly matched tissue to treat an individual disease or disorder***

Scientists may create a new human stem cell line if private funding resources are used***

Why would a person need an adult stem cell transfusion?

When a radiation treatment for cancer has destroyed the person’s stem cells***

Differences between reproductive cloning, therapeutic cloning, and

stem cell research

Goal of reproductive cloning is to create a new organism, human or animal

Goal of therapeutic cloning is to produce embryonic stem cells

The purpose of performing embryonic stem cell research is to develop new and better ways to treat disease

Human stem cell research

2001 legislation allowed federal funding of research using 64 existing human embryonic stem cells

Same legislation declared no federal funds for additional research.

Therapeutic potential of stem cells

Researchers must use existing human stem cell lines for research or find private funding sources

Creation of embryonic stem cells does not use fertilized egg

On the other hand, it does have the potential to become a living thing if transplanted into the uterus

Therapeutic potential of stem cells (continued)

Real advantage of stem cells – permits the production of perfect-match tissue

Scientists have found that embryonic stem cells pick up cues from neighboring cells and differentiate into that cell type

Scientists hope stem cells will be used to treat heart disease, Parkinson’s disease, other disorders of the nervous system