1. 5-2a: Cloning How are mammals cloned?
What is the difference between reproductive cloning and therapeutic cloning?

3. Hello, Dolly! Dolly and her surrogate mother Roslin Institute
Dolly and her lamb, Bonnie
Roslin Institute

4. Mammalian cloning via somatic cell nuclear transfer
Anne McLaren, 2001 Nature 414, doi: /

5. Why has cloning mammals become possible now?
In vitro fertilization technology has come of age. Louise Brown the first “test tube baby” was born in the 1970s.
Nuclear transfer into human eggs is possible for males with defective sperm.
Embryo transfer is routinely used for reproduction of livestock (cattle)

6. How easy (efficient) is animal reproductive cloning?
Dolly was the only lamb from 277 fused eggs
Many animal species have been cloned.
Tetra – rhesus monkey
Copycat
Idaho Gem mule

7. Are cloned animals healthy?
Dolly gave birth to a healthy lamb named Bonnie.
Dolly suffered prematurely from arthritis and other ailments of old age.
Dolly’s telomeres (ends of chromosomes) were shorter than for other sheep of comparable age.

8. Complications in reproductive cloning
Cloned offspring syndrome
Placental abnormalities
Fetus too large
High rate of spontaneous abortions
Early death
Shorter telomeres?
Genes not imprinted properly
Genes that control placental growth, fetal growth inactivated in maternal chromosomes

9. Therapeutic cloning produces embryonic stem cells
Embryonic stem cell colony

10. 5-2b: Stem Cells
What is the difference between embryonic stem cells and adult stem cells?
What legal and ethical issues revolve around cloning and stem cell technologies?

11. Stem cells: undifferentiated cells that can keep dividing to replenish various differentiated cell populations
Totipotent – embryonic stem cells
Pluripotent – bone marrow stem cells
Oligopotent – hematopoietic stem cells
Multipotent – erythropoietic stem cells
Unipotent – reticulocytes

12. Some adult stem cells

13. mammalan development in vitro from egg to blastocyst

14. Human development through blastocyst implantation
© 2001 Terese Winslow,

15. Generating embryonic stem cells for regenerative medicine
Klimanskaya I, N Rosenthal, R Lanza 2008, Nature Reviews Drug Discovery 7, doi: /nrd2403

16. Alternatives to embryonic stem cells?
Induced pluripotent stem cells
Aoi et al. 2008, Generation of Pluripotent Stem Cells from Adult Mouse Liver and Stomach Cells, Science 321:
Retroviral vectors used to transduce 4 transcription factors, incl. c-Myc (proto-oncogene)
ES-like cells in gene expression profile, pluripotency (form tumors containing different cell types, form all 3 major tissue types, germline transmission)