Genetic Engineering Lecture - TeacherWeb

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Dec 14, 2012 (4 years and 9 months ago)

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Genetic Engineering

Vocabulary


Gene


sequence of DNA that codes for a
trait (protein).


Genome


an organism’s complete
genetic information.


Transgenic organism


an organism that
carries a foreign gene in its genome that is
from a different organism.


Recombinant DNA


DNA from two or
more sources that have been combined.

Transgenic Bacteria


Also known as GMOs
(genetically modified
organisms).


Most transgenic bacteria


reproduce every 22
minutes.


Produce a host of
important substances
such as insulin, growth
hormone, and blood
clotting factor.




Transgenic Plants


Chances are you had
some for dinner last
night.


Some species are
capable of producing
own insecticides.



Some GM plants
produce human
proteins and
antibodies to fight
disease.



Transgenic Animals



Have been developed
to study genes in
order to improve the
food industry.


Transgenic livestock
have extra copies of
growth hormone to
grow faster and
leaner meats.

Transgenic Insects


Scientists at UMBI
-
CARB in Rockville,
MD are developing a
transgenic mosquito
that is resistant to
malaria.


Malaria is a disease
caused by a parasite
that is transmitted to
humans by mosquito..

This GM mosquito carries a gene that
confers resistance to the malaria parasite.
Scientists know that the mosquito carries this
gene as the insect's eyes turn fluorescent
green
(Image: PNAS)


Cell Transformation


Also known as gene
splicing or gene cloning.


Bacterial transformations
began in 1977 with a
company called
Genentech.


Herbert Boyer utilized
bacteria called
Escherichia coli

(
E.coli
)
to mass produce human
insulin.

Cell Transformation


Most DNA plasmids contain
genetic markers

such as an
antibiotic resistance and/or
bioluminescent genes.


AMP
r


ampicillin resistance
gene


pGreen


plasmid containing
green fluorescent gene


These genetic markers express
proteins to help scientists
locate the one cell in a million
that has been transformed.

MICROINJECTION TRANSFORMATION



Another technique to
introduce foreign DNA
into a host organism is by
microinjection.



This has helped develop
insects to become
resistance to parasites
that can cause human
diseases such as malaria
or sleeping sickness.

Suction device to hold embryo

Embryo

Microinjection needle

MICROINJECTION TRANSFORMATION

SELECTIVE BREEDING


Producing genetic
variation by using
NATURAL genetic
variations to pass
desired traits to the
next generation.


Results in new plant
varieties, new animal
breeds


A subdivision of a
species.

Labradoodle

SELECTIVE BREEDING


HYBRIDIZATION
-

uses very different
plants to produce
hybrids with
desired traits



INBREEDING
-

uses very similar
animals to keep
the desired traits

Genetic Engineering Tool Kit


Plasmids are special
circular DNA
molecules.


Plasmids are freely
exchanged by
bacteria in the
environment.


Plasmids can be
engineered in a lab to
carry any gene.

RESTRICTION ENZYMES




-

molecular scissors

Restriction Enzymes


Restriction enzymes (RE) are isolated from
bacteria.


They are named from the organism from
which it was isolated.


EcoR1



E


genus name, Escherichia



co


species, coli



R
-

strain



1
-

number


Cut only at a very specific sequence of DNA
nucleotide bases and leave
sticky ends
.

Manipulating DNA


Genes are sequences of DNA that code for a protein or
trait. They are very similar in humans.


Some DNA does not code. This non
-
coding DNA forms
stable, repeating sequences that are different lengths
from person to person.



Restriction enzymes recognize specific sites and can
cut these repeating sequences into fragments that
vary in length.


These pieces of different lengths are called
RFLP
-
restriction fragment length polymorphisms



This makes different numbers and different sized
pieces for every individual human
-

a one
-
of
-
a
-
kind
DNA fingerprint

GEL ELECTROPHORESIS



DNA fragments are loaded into an agarose gel
and separated by size using an electrical
current.



The fragments travel in a specific direction
based on their surface charge.


DNA IS NEGATIVE
. They travel at different
speeds based on their size
-

SMALLER PIECES
TRAVEL FASTER
.


DNA fragments are measured in numbers of
base pairs.


DNA Fingerprinting


VISUALIZATION
-

the
gel is stained with
methylene blue
-

the
DNA bands stain darker
than the background
gel


DNA fingerprint
banding
patterns

are utilized for
medical research or
forensic science.


In 1977 British
scientist Alec Jeffreys
developed the DNA
fingerprinting
technique.


In 1984, DNA
fingerprinting was first
used to solve a
paternity and murder
case.