DNA Cloning: •DNA segment--> plasmid--> bacteria •plasmid replicates •bacteria replicates •Lots of that DNA!

Cloning an Organism:

Genetically identical organisms

Natural Cloning: Spagnum Aspens Lizards, frogs, fish

Armadillos Human twins!

Why artificial clone? Agriculture (apples) Domestic animals Drug production Organ source Race horses!

Cloning is impossible!

Totipotent Stem Cell (Zygote)

Pluripotent Stem Cell

Adult Stem cell

Adult Differentiated Cell

Cell Differentiation:

Lambs cloned (1996)

Using nucleus from an early embryo= totipotent -> totipotent

Dolly the sheep cloned (1997) Somatic-Cell Nuclear Transfer

Adult cell nucleus --> becomes totipotent

BUT Cloning is impossible!

“Prove it! Is Dolly a Clone?”

1998 Mice cloned1998 Cows cloned1998 Last Enderby Cow cloned2000 Pigs cloned2002 CC the cat cloned2003 Horses cloned2003 Rat cloned2005 Dog cloned

Cloning is impossible! (sort of)

Took 277 tries to get DollyNow, only 2-5% success

Cloning is impossible! Problems

DNA programming = epigenetics!

Cloning is impossible! DNA programming = epigenetics!

Cloning is impossible! Problems

Telomeres!!! Dolly was born old

Cloning

is about STEM CELLS

Stem cells: For research How cells differentiate Medical therapies Replace damaged cells and tissue

Zygote -- Totipotent Cell

Early embryo -- Pluripotent

Cells become specialized Multipotent Oligopotent Unipotent

Stem Cell Types

How to obtain STEM CELLS?

Early embryos (totipotent) ESCLater embryos (Pluripotent) ESCCloning

Adult Stem Cells = ASC

Stem cells:

Scientific problems Medical problems Ethical issues

Use Zygote Totipotent

Use Zygote Totipotent

Scientific: Best source of SCMedical: Nonself!Ethical: Taking a human life Origin of the zygotes

Harvest Embryonic Stem Cells

Pluripotent

Scientific: Best source of SCMedical: Nonself!Ethical: Taking a human life Origin of embryos

Sometimes Totipotent (2-5%)Cloning via Somatic-Cell Nuclear Transfer

Scientific: Programming?Medical: Nonself! Or self! ProgrammingEthical: Taking a human life Need eggs - whose?

Adult Stem Cells

Scientific: Do they exist? Pluripotent? Multipotent?Medical: Self!Ethical: None?

Adult Stem Cells: DO THEY EXIST?

Neural stem cells: neurons + glial 1:300 in brain Can get 80% pure SC Works in mice Origin for human use?? Non-self!

Adult Stem Cells: DO THEY EXIST?

Blood stem cells Mulipotent in bone marrow

Induced Pluripotent Stem Cells iPSC

Shinya Yamanaka

Only 4 (later 3) factors neededPut into cell with virusLater use other methods

Induced Pluripotent Stem Cells iPSC

Scientific: Wonderful (are they?)Medical: Self!! Yippie! (or????)Ethical: Are they totipotent??

Induced Pluripotent Stem Cells iPSC

Scientific: Programming!Medical: Programming!Ethical: Are they totipotent??

Induced Pluripotent Stem Cells iPSC

The Benjamin Button Cell

“There were no troublesome memories in his childish sleep.”

iPSC have memories!

Epigenetic effects remain!

A Stem Cell Zoo:ESC (embryonic)ESCNT (Embryo nucleus)SCNT (somatic cell nuclear transfer)ASCiPSC

The 800 Pound Ugly Gorilla

CANCER