cloning. what do you think cloning is? when do you think scientists first started talking about...
TRANSCRIPT
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.
2000 – 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.
2005 – Successful cloning of a dog.
2005 – South Korean research is found to be fraudulent
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