Cloning In biotechnology, cloning refers to the different processes used for duplicating biological material (ex. DNA fragments, cells or organisms).

The 3 Types of Cloning Technologies: 1. Recombinant DNA Technology/DNA Cloning Transfer DNA fragment from one organism to a bacterial plasmid (self-regulating) Isolate DNA fragment with gene of interest from chromosomal DNA Isolate DNA fragment with gene of interest from chromosomal DNA Join the DNA fragment with a plasmid to create recombinant DNA Join the DNA fragment with a plasmid to create recombinant DNA Introduce recombinant DNA into suitable host cell for reproduction with host cell DNA Introduce recombinant DNA into suitable host cell for reproduction with host cell DNA

The 3 Types of Cloning Technologies: 2. Reproductive Cloning (“Dolly”) Generate an animal with the same nuclear DNA as another currently or previously existing animal (Somatic Cell Nuclear Transfer) Transfer genetic material from nucleus of donor adult cell to an enucleated egg (egg without a nucleus and no genetic material) Transfer genetic material from nucleus of donor adult cell to an enucleated egg (egg without a nucleus and no genetic material) Reconstructed egg with DNA from donor cell is stimulated to allow for cell division (chemicals/electric current) Reconstructed egg with DNA from donor cell is stimulated to allow for cell division (chemicals/electric current) Cloned embryo reaches a suitable stage and is transferred to uterus of a female host (for development  birth) Cloned embryo reaches a suitable stage and is transferred to uterus of a female host (for development  birth) **Not truly an identical clone!

Animals that have been cloned: Tadpole (1950) Sheep (Dolly – , 1 success out of 276 tries) GoatsCowsMicePigsCatsRabbitsGaur

The 3 Types of Cloning Technologies: 3. Therapeutic Cloning “Embryo cloning”: production of human embryos for use in research in research Harvest stem cells for use in studying human development and to treat disease Cells can be used to generate almost any type of specialized cell in human body Cells can be used to generate almost any type of specialized cell in human body Cells extracted from egg after division for 5 days (blastocyst stage) Cells extracted from egg after division for 5 days (blastocyst stage) Extraction process destroys embryo (*Ethical concerns**) Extraction process destroys embryo (*Ethical concerns**) Perhaps stem cells can one day be used to replace cells to treat heart disease, Alzheimer's, cancer, and other diseases Perhaps stem cells can one day be used to replace cells to treat heart disease, Alzheimer's, cancer, and other diseases

Cloned Organs for use in Transplants Scientists hope that one day therapeutic cloning can be used to generate tissues and organs for transplants TO DO THIS… Extract DNA from person in need of a transplant and insert into an enucleated egg Egg with patient's DNA starts to divide Embryonic stem cells are harvested Stem cells would be used to generate an organ or tissue that is a genetic match to the recipient The cloned organ could then be transplanted into the patient without the risk of tissue rejection **If organs could be generated from cloned human embryos, the need for organ donation could be significantly reduced.

Challenges and Risks More effective technologies are needed Expensive Low success rates -more than 90% of cloning attempts fail to produce viable offspring -more than 100 nuclear transfer procedures could be required to produce one viable clone Cloned animals may have compromised immune function, higher rates of infection, tumor growth and other disorders Early/mysterious death, abnormally large, do not live long enough to generate good data about how clones age, gene expression abnormalities

Should Humans Be Cloned? Due to inefficiency (only 2% success rate) and lack of understanding about reproductive cloning, many scientists and physicians strongly believe that it would be unethical Most attempts to clone mammals fail ~ 30% of clones born alive are affected with "large- offspring syndrome" and other debilitating conditions ~ 30% of clones born alive are affected with "large- offspring syndrome" and other debilitating conditions Several cloned animals have died prematurely from infections and other complications. Several cloned animals have died prematurely from infections and other complications.

Should Humans Be Cloned? The same problems would be expected in human cloning Scientists also don’t know how cloning could impact mental development. Scientists also don’t know how cloning could impact mental development. While factors such as intellect and mood may not be as important for a cow or a mouse, they are crucial for the development of healthy humans With so many unknowns, the attempt to clone humans at this time is considered potentially dangerous and ethically irresponsible. With so many unknowns, the attempt to clone humans at this time is considered potentially dangerous and ethically irresponsible. What do YOU think?