1. Dolly
1st experimentally cloned animal

2. Microinjection of nuclei into eggs

3. Reproductive cloning requires epigenetic modifications to be reset to state in fertilized egg.
But, this doesn’t work perfectly.
Not yet clear what health problems may arise due to misexpression of many genes.

4. Clones = Genetically identical individuals
Two Kinds of Animal Cloning
Reproductive Cloning:
Remove nucleus from egg cell Replace it with nucleus from somatic cell (e.g., skin cell) Stimulate cell to divide (like a fertilized egg).
Implant embryo into surrogate mother.
Therapeutic Cloning (Nuclear Transplantation):
Start the same, but stop development at blastocyst stage. Remove inner cell mass cells and use to create embryonic stem cell line.

5. Stem Cells
Unspecialized cells that renew themselves by dividing an unlimited number of times.
Under certain conditions they can give rise to cells with specialized functions.
Embryonic Stem Cells:
Derived from undifferentiated cells from early-stage embryos (blastocyst stage).
Pluripotent: Have the potential to give rise to any kind of cell in the body.

6. Therapeutic Cloning
2. Induce cells to develop into specific cell type that patient needs
1. Make embryonic stem cell line from patient

7. Use to treat diseases such as Parkinsons or diabetes (right)

8. Mature neurons (red) and glial cells (green)
derived from human embryonic stem cells

9. Blood cells (red) derived from human embryonic
stem cells

10. Can combine stem cell & gene therapy
Replace bad copy of gene with good one
Make embryonic stem cells from “patient”

11. Stem Cells
Unspecialized cells that renew themselves by dividing an unlimited number of times.
Under certain conditions they can give rise to cells with specialized functions.
Embryonic Stem Cells:
Derived from undifferentiated cells from early-stage embryos (blastocyst stage).
Pluripotent: Have the potential to give rise to any kind of cell in the body.
Adult Stem Cells:
Found in a variety of tissues and organs.
Multipotent: Able to give rise to a limited range of cell types.

12. Adult Stem Cells Multipotent Bone marrow Blood stem cells
Stromal stem cells

13. Some adult stem cells may be pluripotent
This potential ability to differentiate into wider array of cells is called plasticity.
How may plasticity be regulated???

14. Adult Stem Cells Potential Uses: Bone marrow transplants.
Hope to be able to get adult stem cells to differentiate into wider range of cell types.
May be able to regenerate tissues using cells from one’s own body, avoiding tissue rejection problems.
Limitations: May be limited in range of cells they can give rise to. e.g., Blood stem cells may be able to produce blood cells, but not brain cells.
Can only obtain a relatively small number of cells from an individual & they don’t grow well in culture.

15. Challenges in stem cell therapy
Learn what causes stem cells to become distinct kinds of specialized cells, such as insulin-producing pancreatic cells or nerve cells, and how to more precisely control this process.
Demonstrate plasticity of adult stem cells and learn how to control this.
Overcome technical (& political) barriers for working with human embryonic stem cells.