Attack of the Clones!

REVIEW Asexual cloning occurs in nature Plants and less complex organisms

can all duplicate trough asexual methods

Complex, multicellular organisms have lost ability to asexually reproduce • Cells have become too specialized

Human Assisted Cloning Can be used to save the DNA from

endangered species or mass produce organisms with desirable traits

There are two types of cloning we’ll discuss: 1. Reproduction Cloning 2. Therapeutic Cloning

Reproductive Cloning Also called adult DNA cloning

Purpose: to create a genetic duplicate of an existing (or previously existing) organism with desirable traits

Because the cells are specialized, you can’t just turn a single skin cell into a

new individual!

Dolly, the World’s Most Famous Cloned Sheep

July 5, 1996 – Feb. 14, 2003 cloned from the cell of a mammary gland Was able to reproduce

How did they do it? There are 5 steps in the therapeutic

cloning process:

1. Remove nucleus from an egg cell2. A mammary gland cell is removed

from an adult female3. Electricity fuses mammary and egg cell4. Fused cell begins dividing5. Dividing embryo is inserted into

surrogate mother

Problems Scientists Encountered only about 10% of clones usually

survive Surviving clones can be abnormally

large and experience higher rates of infection and cancer

For example, before Dolly died of a lung disease she appeared to be aging faster than other sheep.

Therapeutic Cloning used to correct health problems uses human embryonic stem cells and

adult stem cells

Stem Cells: cells that have the potential to become many different types of cells

Embryonic Stem Cells: more desirable because they can become any one of our 200 types of body cells

Stem cells can be used to replace damaged cells in patients with diabetes, spinal cord injuries, and Parkinson’s disease.

Embryonic stem cells are often used Adult stem cells are not as adaptable

Adult stem cells form bone marrow have been used in transplants for 30 years• Have recently been used to regenerate

nerves and heart tissue, and to treat diabetes

Controversial because the best stem cells arefrom embryos which are destroyed when harvesting cells