Good Biology Gone Bad at the Movies Jurassic Park Thursday, January 13th Melissa Kosinski-Collins

Types of Cloning Recombinant DNA/ DNA cloning: Transfer of DNA from one organism into an autonomously replicating piece of DNA (i.e. plasmid) in another organism Reproductive cloning: Somatic cell nuclear transfer Therapeutic cloning: Embryonic cloning to produce stem cells used in research

Reproductive Cloning: Methods Extract nucleus (including nuclear DNA) from adult cell using needle Artificially introduce DNA into an egg cell without a nucleus of the same species Treat fused egg with chemicals or an electrical current to stimulate development When the fused embryo is large enough, transplant into a surrogate mother of the same species for development http://www.columbia.edu/cu/opg/images/dna.jpg

Genetically modified mouse ES cells and mouse microinjection

Cloned Animals “Dolly”: the world’s first cloned adult animal “Copycat”: December 22, 2001, the world’s first cloned pet “Idaho Gem”: May 4, 2003, the world’s first cloned race horse “ANDi”: First rhesus monkey cloned by embryo splitting http://www.guardian.co.uk/gall/0,8542,627251,00.html

Reproductive Cloning: Drawbacks DNA must not be significantly damaged during implantation process Many nuclear transfers needed for small number of successful growths (1/276 for Dolly & 1/191 for Copycat) Clones are often born with birth defects or predisposition to disease http://the.honoluluadvertiser.com/dailypix/2001/Mar/29/ln11a_b.jpg

Reproductive Cloning: Challenges As an embryo grows, cells move from an undifferentiated to a differentiated state DNA extracted from adult cells is terminally differentiated We must get DNA from adult cells to “revert” to undifferentiated state to form the new clone! Altered expression state of genes from adult DNA may be causing the high number of cloning failures 2002 WI study showed 4% of genes in cloned mouse liver and placenta function abnormally

Are these really clones? Mitochondrial DNA Selective X inactivation Nature versus nuture Random Mutation Lysogenic virus infection http://www.guardian.co.uk/gall/0,8542,627251,00.html

Could we bring back extinct species? What about a surrogate for embryo transplantation? Where do we get the DNA from? How do we fix DNA that has been damaged? http://www.aoqz76.dsl.pipex.com/Web%20Page%20Components/Wallpaper/Movies/Jurassic%20Park.jpg

Things to Watch For Where do they get the DNA? Do they have a donor nucleus or an acceptor annucleated egg cell? What template do they use to “fix” breaks in the dinosaur DNA? How do they physically manipulate the DNA? Do they have any failures in the cloning process? If so, what and where are they?

Human Cloning November 2001, ACT announces they have produced the first cloned human embryos Implanted skin cell DNA into a nucleated human egg Stimulated division with Ionomycin 3 of 8 eggs actually began dividing 1 of 8 divided until it was stopped at 6 cell stage