Genetic Engineering and Other Aspects of Biotechnology


11 Δεκ 2012 (πριν από 8 χρόνια και 7 μήνες)

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3.4 Genetic Engineering and Other Aspects of Biotechnology

PCR (polymerase chain reaction) copies and amplifies minute quantities of nucleic


and 3.4.3

Electrophoresis involved the separation of molecules by size and charge.
This can

be done with DNA fragments on a bed of agar, and is used in almost every
technique below using DNA, but especially DNA profiling.

3.4.4. Two applications of gene profiling are

DNA fingerprinting for criminal cases


collect samples of DNA
containing substance (blood, semen)

> from suspect

> from crime scene


amplify quantity using PCR if necessary


add endonucleases to produce DNA



use gel electrophoresis to separate
fragments based on size (small
fragments move furthest)

into DNA fingerprint


compare samples from crime scene and suspect for match

II. DNA fingerprinting to determine identity



samples of DNA
containing substance (blood, semen)

> from living descendants of Tsar of Russia

> from presumed remains of Tsar of Russia


amplify quantity using PCR if necessary


add endonucleases to produce DNA RFLPs


use gel electrophoresis to separate RFLPs into DNA fingerprint


compare samples from descendants of Tsar of Russia and presumed remains of Tsar of
Russia for match

3.4.5 DNA screening is testing an individual’s DNA to see if th
ey have a certain allele of a
gene present or absent.



natal diagnosis of genetic disease: sickle cell anemia


may allow pre
natal and post
natal treatment


allows for the option of abortion


allows for identification of

carriers, which provides information necessary for genetic
counseling/probability of passing on alleles to offspring

Further discussion of Advantages
: Prenatal and postnatal tests for diseases that can be treated if
diagnosed early. These include PKU, an
d also the metabolic diseases MCAD, VLCAD, and the other
metabolic diseases meet that ethical requirement. They can be killers when unknown. But when
diagnosed, many are easily treated

and all can be treated in ways that will save the baby and the
family u
ntold pain and anguish. MCAD, for example, is a disease that interferes with the ability to
convert fat into life
sustaining ketones and energy. Children with MCAD, among the most common
of the 30 disorders, cannot use the usual fuel reserves stored in the
ir fat. If they are denied food for
extended periods, usually 12 hours or more, they can suddenly get sick and even die. While babies
and young children rarely go that long without food, if a virus with accompanying vomiting and
diarrhea hits, it could kil
l them. (Try


DNA screening is used to diagnose inherited disorders in both prenatal and newborn babies in
hospitals around the world. These disorde
rs may include cystic fibrosis, hemophilia, Huntington's
disease, familial Alzheimer's, sickle cell anemia, thalassemia, and many others.

: These are mainly of the socio
economic variety, but should not be downplayed.
Bartha Maria Knoppers,
the chair of the Ethics Committee of the Human Genome Organization
says that “employment and insurance are two of the most tangible ways in which genetic screening
can be used to the detriment of individuals.” She says that employers and insurers who have
to genetic information will be able to discriminate against the very people whom the genetic
revolution is supposed to help

those with congenital conditions.

3.4.7 and 3.4.8.
Human Genome Project is an international cooperative venture
d to sequence the complete human genome
. Some people (I am not so
convinced and it has cost a lot of money)

Increased understanding of genetic diseases may allow treatment through
development of new pharmaceuticals

Increased understanding of genetic dise
ases may allow genetic counseling through
improved genetic screening for genetic disease predispositions


Because the genetic material of all organisms is made of the same material (DNA),
meaning it is universal, genetic material can be transferred from on
e organism to
another relatively easily.

For example,
genetically modified cows


contain human genes for making medically important proteins (insulin, growth hormone)


human proteins are extracted from cow’s milk and sold as pharmaceutical

Examples from agriculture include


(see last page)

Bt corn: corn plants with a gene form the bacteria bacillus thuringiensis providing
protection from European corn borer disease. Less pesticide needed higher yield.

Xa21 rice
: Transgenic rice resistant to fungus. Gene allows plants to initiate a defense
response to fungal attack (see

for more)

Gene for amylase inhibitor transferred to pea plants protecting agai
nst pests that digest

Gene from Brazil nut introduced to haricot bean to increase nourishment

Papaya strains, sun
up and rainbow, which are ringspot virus resistant

Salt tolerance genes introduced into salt
sensitive wheat plants

3.4.12. Potential
benefits of gene transfer include (in addition to the obvious benefits from
having more productive plants) more specific breeding and less wastage. But the possible
dangers include

Potential escape of genetically engineering plants from cultivation

ompeting naturally occurring varieties, thus becoming super weeds

altering entire ecosystem interactions

3.4.10. Method of gene transfer.

3.4.13 Gene therapy can be used to treat
SCID (severe congenital immune

is a genetic disease caused by a recessive allele in the homozygous
condition preventing the production of the enzyme ADA (adenosine
deaminase), causing malfunction of leukocytes (white blood cells) leading to
death through immune failure


3.4.16 Clones are
a group of genetically identical organisms (these can be naturally
occurring in asexual organisms) or a group of cells artificially derived from one parent cell.

The big development in the past 10 years is that c
ells from grown organisms


have been used to clone into full organisms (the obvious example is Dolly the sheep)

arguments for

identical twins are basically clones and yet are individuals, may result
in better IVF techniques.

ments against

sanctity of life, cloning will lead to discrimination if some are
cloned just for organ donation,

Some Genetically Modified Foods data