The Future Isn't What It Used to Be: Biotechnology

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23 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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Biotechnology

15.1 What Is Biotechnology?



Biotechnology can be defined as the use of technology to control biological processes
as a means of meeting societal needs



At its most basic level, biotechnology includes animal and plant breeding



Biotechnology is
a broad category that currently encompasses:

o

The production of transgenic organisms

o

Techniques to clone animals

o

The reprogramming of cells to become different types of cells

o

The use of biotechnology in forensics

15.2 Transgenic Biotechnology



A
transgenic o
rganism

is an organism whose genome carries one or more genes
from another species



Many biotechnology products are produced within transgenic organisms




The production of transgenic organisms makes use of recombinant DNA technology



This makes use of enzyme
s normally produced in bacteria

o

Restriction enzymes

o

DNA ligase




DNA from any organism (including humans) can be inserted into plasmid DNA



Plasmid DNA is isolated from bacteria



Researchers use the same restriction enzyme on both the human DNA of interest an
d
the plasmid DNA



Cutting both the target DNA and the plasmid DNA with the same restriction enzyme
gives complementary “sticky ends”, allowing splicing of the human DNA into the
plasmid



This produces
recombinant DNA




A
cloning vector

is a self
-
replicating
agent that functions in the transfer of genetic
material

o

Plasmids are useful cloning vectors

o

Bacterial viruses (bacteriophages) are also useful cloning vectors




The same recombinant DNA techniques are used to make other transgenic organisms

o

Like golden ric
e enriched for beta carotene

o

or transgenic goats producing important proteins in their milk

o

or even cows producing hypoallergenic milk



2
-
3% of babies are allergic to cow milk and experience diarrhea and
vomiting

15.3 Reproductive Cloning



A clone is a gene
tically identical copy of a biological entity



Reproductive cloning is the process of making clones of animals with a defined
genotype and phenotype



Many mammals have been cloned using this process




Dolly the sheep was the first animal cloned using cells fr
om an adult animal



Today, reproductive cloning of mammals is carried out through variants of the
process that was used with Dolly



This process is called somatic cell nuclear transfer (SCNT)

o

In SCNT, the nucleus of an egg cell is removed and the enucleated
cell is
fused with an adult cell containing a nucleus and the DNA of the adult cell

o

The fused cell then starts to develop as an embryo and is implanted into a
surrogate mother




The first cloned cat was named Copy Cat, CC for short




The first cloned dog was

named Snuppy



The adult cells came from a male Afghan named Taj



Only one pregnancy out of many gave a successful clone




Other mammals have been cloned



Including the endangered bateng


15.4 Cell Reprogramming



Most cells in the adult human body have undergon
e commitment, a developmental
process that results in cells whose roles are completely determined



Two promising methods exist for generating human cells that are needed to treat
victims of accident or disease:

o

Production from embryonic stem cells

o

Productio
n through induced pluripotent stem cells (iPS)

o

Both methods reprogram the cells to give the desired cell type




Embryonic stem cells

(ESCs)
from the blastocyst inner cell mass can give rise to all
the different cell types in the adult human body



In stark co
ntrast, adult stem cells are rare, only found in certain tissues, and only
capable of producing one or a few different cell types



In 2007, two research teams developed a type of human stem cell not derived from an
embryo: the induced pluripotent stem cell
(iPS cell)



Initially, these were produced by introducing four developmental genes into the
genomes

of ordinary adult skin cells




We are learning more and more about these iPS cells and their capabilities



Although they seem to have some of the capabilities

of ESCs, there appear to be some
fundamental differences



More research is needed

15.5 Forensic Biotechnology



The identities of criminals, biological fathers, and the victims of disasters are often
established through the use of forensic DNA typing




The
po
lymerase chain reaction (PCR)

has proven to be incredibly useful for DNA
typing



It allows the amplification of small amounts of DNA




Forensic DNA typing most commonly works by comparing short tandem repeat (STR)
patterns that are found in all human genomes


15.6 Controversies in Biotechnology



Progress in biotechnology often comes slowly because so many of the processes being
developed are not just new, but also controversial



One notable biotech controversy concerns genetically modified organisms (GMOs)



Oppo
nents of genetically modified consumer products are concerned about their
effect on human health and the environment

o

There is no evidence so far that GM crops have had detrimental effects in
either area

o

But consumer resistance to the crops has sharply limi
ted both the types
being planted and the types being put into development

o

November 2012
-

Proposition 37 deals with possible mandatory labeling of
consumer products containing GMOs




Some biotech controversies are essentially ethical in nature



Among these a
re the controversies concerning embryonic stem cells and therapeutic
cloning




A more general controversy has to do with the question of what level of regulation
society ought to impose on the modification of living things