Biotechnology

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14 Δεκ 2012 (πριν από 4 χρόνια και 8 μήνες)

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Biotechnology

Cloning

Genetically
modified food

Four hot topics in biotechnology:

Stem Cells

DNA
Fingerprinting

Biotechnology
: the
engineering of organisms
for useful purposes.

A chimera, a mixture of a goat and a
sheep.

Biotechnology

Animal Cloning

Megan and Morag, the world’s first cloned
mountain sheep.

Why Clone
Animals?

1. To
answer questions of
basic biology

2. For
herd
improvement

4. To make us happy
(e.g
. pet cloning
)

3. For
pharmaceutical
production

Prometea
, the first cloned horse (in
foreground) with her identical twin and
surrogate mother Stella
Cometa
.

Utah State
University

(And Idaho State)

First Cloned Mule

Egg Cell

Udder Cells

1.
An egg is taken from
the surrogate mother

2.
A needle removes the
DNA from the egg cell.

3.
An udder cell (or other
somatic cell) is taken
from the organism
being cloned.

4.
The “blank” egg cell is
fused with the udder
cell.

5.
Electricity stimulates
the fused cell to begin
dividing into an
embryo.

http://www.jpvpk.gov.my/html/news/archives/English/Feb02%2016B.htm

The First
Cloned Pet

Carbon
Copy is
not a
phenotypic
carbon
copy of the animal
she was cloned from.

(Science (2002) 295:1443)

This is “Carbon
Copy”…the first
cloned pet.

Rainbow and her clone “cc”

http://drsophiayin.com/blog/entry/cloning
-
cats
-
rainbow
-
and
-
cc
-
prove
-
that
-
cloning
-
wont
-
resurrect
-
your
-
pet

The First
Cloned Pet

If they are clones, why
aren’t the identical?

The genes that controls
coat color can be active or
inactive in each skin cell.
This is a random process.
Even though CC has the
gene for orange spots,
that gene has been
“turned off”

Read more about these un
-
identical clones
here
.

Is Animal Cloning Ethical?

The first cloned horse and her surrogate
mother/genetic twin.

The answer can’t be determined by
scientists alone.

Stem Cells

A stem cell is a cell that has not yet been assigned a
specific function.

During development the stem cells become specialized

Stem Cell

Nerve Cell

White Blood Cell

Skin Cell

Stem Cells

This specialization is terminal.

That means that once a cell has been specialized it
can only produce more cells like it.

White Blood Cell

White Blood Cell

One of the best sources for stem cells is an
embryo of a developing fetus.

Stem Cells

Where can you find stem cells?

This is a four day
old embryo called a
blastocyst
. Each of
these developing
cells is a stem cell!

FYI: When stem cells are harvested, the embryo is
destroyed and can no longer grow into a fetus

Stem Cells

What do scientists do with stem cells?

Researchers believe that stem cells can be
used to replace damaged tissue caused by:


Cancer

Multiple Sclerosis

Parkinson’s Disease

Spinal Damage

Ethical
Questions

If stem cells are taken
from these masses,
are you destroying
life?

Are these masses
of cells a human?

More Ethical Dilemmas

At what point does an embryo
become a
human
?


Is it ethical to use
“extra” or “left over”
embryos from
In Vitro
fertilization for stem
cell research?


If your grandfather developed a disease
that could possibly be cured using stem
cells,
would you donate

an embryo?

Stem Cells

There ARE other sources for stem cells, but they
are believed to be inferior to embryonic stem
cells:

Bone Marrow

Lipid cells

DNA
Fingerprinting

A DNA fingerprint used in a
murder case.

What are we looking at?

The defendant stated that the
blood on his clothing was
his,
was he telling the truth?

DNA
Fingerprinting

Different individuals carry different
alleles.

Most alleles useful for DNA fingerprinting differ on the
basis of the number of repetitive DNA sequences they
contain.

DNA
Fingerprinting

DNA can be cut up in pieces
of alleles. Each piece is a
different size.

A DNA fingerprint is made by
analyzing the sizes of DNA
fragment.

The DNA Fragments Are Separated on
the Basis of Size

The technique is gel electrophoresis.

The pattern of DNA bands is compared between each sample
loaded on the gel.

DNA Electrophoresis
Animation

Genetically Modified Foods

We genetically modify our food for disease
resistance, to change its taste, and to make it
grow faster and larger.

Genetically Modified Foods

What is the controversy?

A branch of government called the “Food and
Drug Administration” (
FDA
) is responsible for
determining if a food or drug is “safe”

For example, genetically modified salmon:

The FDA treats this as an
animal drug and
not a food
. This means they have a very
narrow definition of “safe” and do not
necessarily run the correct tests on the
salmon before we eat it.

http://www.sciencemag.org/content/330/6007/1052.full.pdf

Genetically Modified Foods

However, many organizations have
used what we DON’T KNOW about
GM foods to try to stop genetic
engineering of foods all together.

The “Indian Institute of Science” noted
that people have been eating GM corn
for more than a decade in several
countries, and
there have been no
related health issues reported
.

http://www.nature.com/nature/journal/v480/n7377/pdf/480321d.pdf

Methods for Plant Genetic Engineering are
Well
-
Developed and Similar to Those for
Animals

Golden Rice is
Modified
to
Provide a Dietary
Source of Vitamin A

Worldwide, 7% of children suffer vitamin A deficiency, many of
them living in regions in which rice is a staple of the diet
.


However, many of these same regions have banned GM foods

Golden rice (yellow) with standard rice (white).

Here in the U.S. more GM crops are grown each year:

Genetically Modified Crops

Genetically Modified Cotton

(contains a bacterial gene for
pest resistance)

Standard
Cotton

Biotechnology

Let’s summarize:


Four of the most talked about biotechnology
efforts are in
cloning
,
stem cell research
,
DNA fingerprinting
, and
genetically
modified foods
.


Advances in biotechnology
raise ethical
questions

that scientists alone cannot
answer.