In the movies when the crazy evil scientist
wants to make a clone he creates a giant
incubation chamber full of oozing slime, and from
this a body begins to emerge. This looks super
cool and is good for the movies, but in the real
world creating a clone is nothing like this!
Normally when two people have a baby half of
the chromosomes (DNA) come from the mother and the
other half come from the father. This is
established at meiosis when the egg and
sperm are produced, each with half of the total
chromosome number. Then, when the sperm enters
the egg, its chromosomes match up with the
chromosomes already in the egg, creating a cell
with the full number of chromosomes which then
divides and grows to form a baby. Half of the
chromosomes in the baby came from the father, and
the other half from the mother. Throughout
history, in order to have a baby, there had to be
a father and a mother.
However, scientists have now figured out a way
around this. First, they take an egg from a woman
who is willing to donate one of hers. Then they
suck out the chromosomes (DNA) from inside the
egg. Now that they have an egg with no DNA in it,
they can put in the DNA from anybody they want!
To do this, they take a normal cell (not an egg or
sperm) from the "parent" and remove its DNA.
(Remember that a normal cell already has all 26
chromosomes). They then inject this DNA into the
egg, forming an egg cell with all 26 chromosomes--
just as if it had been fertilized by a sperm!
However, this new "fertilized" egg is very
different, because all of the DNA came from just
one person instead of two! The scientists can zap
the egg with electricity or give it special
chemicals to make it start to divide, and then
they have to put it back inside a woman's womb so
that it can grow into a baby in the normal way.
(If you think about it, men still need women to
have babies-- but women don't really need men!)
When the baby is born, it will have the exact
same DNA as the person who donated the cell, and
therefore the baby is called a "clone". If the
scientists ever made a clone of you, it would be a
lot like having an identical twin-- only your
twin would have just been born as a baby!
Many scientists are very excited about cloning.
Not only does cloning help us to better
understand the process of human development, but
it may also have a lot of useful medical
applications. For example, many people hope that
one day cloning will make it possible to grow
new body parts that are exactly like the original
one was, or to develop treatments that would
reverse the problems of aging or help cure genetic
diseases. However, many people are against
cloning, because they think we shouldn't tamper so
much with life. There are many things that we
still don't understand. Many of the animals that
have been cloned have developed problems later in
life that show the cloning isn't perfect, and so
it may be very scary to make a human baby clone
who will suffer because of the problems. Also
people are scared that clones will be treated like
slaves or animals or medical experiments, when
really they are people also.
What do you think about cloning? Do you
think it's exciting, scary, or both?
A clone is an individual who has exactly the
same genes as another individual. You might think
cloning is new, but you can make a clone yourself!
Just find someone you know who really likes
plants; maybe a relative, your teacher, or a
friend. They can show you how to grow a new plant
from a piece cut off of one of their plants. It
will be a clone of the first plant.
Animal clones are a lot more rare. Dolly the
sheep and CC (for carbon copy) the cat are both
clones. They were created by making an egg cell
with the genes of an adult animal.
Here are a few things you need to know to
understand animal cloning. Each cell has a
nucleus, which contains the genes (recipes) for
making an individual. Almost every cell in an
individual's body has the same genes in it. There
are 2 exceptions: red blood cells in mammals and
reproductive cells (egg or sperm cells).
Every reproductive cell an individual makes is
different. When an egg and sperm cell get
together, they make unique individuals.
In cloning, researchers take an egg cell and
remove the nucleus. Then they take the nucleus
from an adult animal and put it in the egg. Now
there's an egg cell with the exact same genes as
the adult who donated the nucleus. They get the
egg to start dividing, then put it in a female
animal that is ready to carry the pregnancy. If
all goes well, you get a kitten or lamb (or
whatever) that has exactly the same genes as the
animal that donated the nucleus.
The surprising thing is that the clone may not
be too much like the original. Check out this
picture of Rainbow and her clone.
CC: copycat .
You'll notice they don't look much alike. That's
because the environment, even inside the mother,
also makes individuals what they are.
But you asked about humans. The process would
theoretically be the same, but a lot of people
question whether it's a good idea. It took over
87 tries to get a healthy cat clone. Some
organizations are also against cloning pets
because there are already millions of pets who
need homes. On the other hand, some people think
that cloning farm animals will make it easier and
cheaper to raise them.
There's no proof that anyone has every cloned a
human yet. A group recently claimed that they
had. However, they have not provided any
There are humans who are genetically identical
to each other. Who are they?
Thanks for asking.
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