Problems with cloning

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Transcript Problems with cloning

Cloning

What do you think cloning is?
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When do you think scientists first
started talking about cloning?
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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.
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Types of Cloning
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Reproductive cloning – making an
organism with the same nuclear DNA.
Sometimes called nuclear transfer.
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Therapeutic cloning/embryo cloning Using human embryos for research
“stem cells”
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DNA cloning – recombinant DNA –
adding genes to other organisms.
Cloning Timeline
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1938-German scientist suggested that
animals can be cloned by fusing an
embryo with an egg cell
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1952 – first attempt at cloning –
FAILED
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1970 – Cloning attempted with frogs –
grew to tadpoles before dying – no one
could repeat the experiment with
success.
Cloning Timeline
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1981 – reported that two mice had been
cloned from embryo cells
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1982 – was determined that the mice cloning
was a fraud
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1984 – cloned sheep, cattle, pigs, goats,
rabbits and monkeys from embryo cells
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1997 – successfully cloned a sheep, Dolly,
from an adult cell – called a nuclear transfer.
Cloning Timeline
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1997-present – continue cloning of
many different animals including sheep,
pigs, goats, mice, cows, cats, dogs,
rabbits and a guar.
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2000 – cloning of a baby bull from a
cloned bull (re-cloning) is successful
Cloning Timeline
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2004 – South Korean researchers
reported they created 30 human
embryos through cloning and produced
stem cells from each.
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2005 – Successful cloning of a dog.
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2005 – South Korean research is found
to be fraudulent
Steps of Cloning – Nuclear Transfer
Click and clone….
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http://learn.genetics.utah.edu/content/te
ch/cloning/clickandclone/
Reasons for cloning:
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Recreate extinct animals
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Preserve endangered animals
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Reproduce animals prized for certain
traits – example disease resistance
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Create animals that produce human
medication
Reasons for cloning:
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Create animal models of disease for studying
transmission, treatment, and prevention
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Obtain organs for transplanting
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Reproduction (not able to have children,
children died)
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Recreating a deceased pet
Problems with cloning:
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Success rate of cloning is only 2-4%
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Clones 3x more likely to die
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Underdeveloped lungs
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Larger than normal – enlarged organs
Problems with cloning:
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Susceptible to infections
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Lack of genetic diversity to overcome
simple environmental problems.
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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
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Making a designer baby
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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 10-15
thousand dollars.
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