Cloning

What do you think cloning is? When do you think scientists first started talking about cloning? When do you think they first attempted cloning?

What is Cloning? Cloning is making an identical genetic copy of an organism. Has occurred for thousands of years in plants. Identical twins are “natural” clones Cloning has more recently been attempted in animals – gaining attention.

Types of Cloning Reproductive cloning – making an organism with the same nuclear DNA. Sometimes called nuclear transfer. Therapeutic cloning/embryo cloning - Using human embryos for research “stem cells” DNA cloning – recombinant DNA – adding genes to other organisms.

Cloning Timeline 1938-German scientist suggested that animals can be cloned by fusing an embryo with an egg cell 1952 – first attempt at cloning – FAILED 1970 – Cloning attempted with frogs – grew to tadpoles before dying – no one could repeat the experiment with success.

Cloning Timeline 1981 – reported that two mice had been cloned from embryo cells 1982 – was determined that the mice cloning was a fraud 1984 – cloned sheep, cattle, pigs, goats, rabbits and monkeys from embryo cells 1997 – successfully cloned a sheep, Dolly, from an adult cell – called a nuclear transfer.

Cloning Timeline 1997-present – continue cloning of many different animals including sheep, pigs, goats, mice, cows, cats, dogs, rabbits and a guar – cloning of a baby bull from a cloned bull (re-cloning) is successful

Cloning Timeline 2004 – South Korean researchers reported they created 30 human embryos through cloning and produced stem cells from each – Successful cloning of a dog – South Korean research is found to be fraudulent

Steps of Cloning – Nuclear Transfer

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Reasons for cloning: Recreate extinct animals Preserve endangered animals Reproduce animals prized for certain traits – example disease resistance Create animals that produce human medication

Reasons for cloning: Create animal models of disease for studying transmission, treatment, and prevention Obtain organs for transplanting Reproduction (not able to have children, children died) Recreating a deceased pet

Problems with cloning: Success rate of cloning is only 2-4% Clones 3x more likely to die Underdeveloped lungs Larger than normal – enlarged organs

Problems with cloning: Susceptible to infections Lack of genetic diversity to overcome simple environmental problems. In primates, spindles do not form correctly – problems with cell division

Most scientists say….. Think of cloning as being one type of “tool” that could be used in science and technology. The tool is not bad or good. It is what is done with the tool that becomes bad or good.

Designer Babies Gene technology may allow parents to select traits they want in their children Currently being used to check for males or females, presence of some diseases First done in 1990 In the future could be expanded to examine embryos for physical and mental traits

Making a designer baby In order to check for traits: –Eggs must be removed from woman –Eggs fertilized in petri dish with sperm –Embryos begin division –One cell removed –Cell’s DNA is screened for particular trait or sex of child

Making a designer baby Only embryos that have the correct DNA makeup are implanted into the woman If procedure is successful embryos will grow to full-term healthy children Current cost is estimated at thousand dollars.