Download Genetic Engineering Techniques

Genetic Engineering Techniques
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Restriction Enzymes
DNA Recombination
DNA Insertion
DNA Sequencing
Transgenic Bacteria, Plants, and Animals
Cloning
Gel electrophoresis
Genetic Engineering Techniques
• Restriction Enzymes:
– Genes can be cut at specific DNA sequences by proteins
known as Restriction Enzymes
– Each recognizes and cuts DNA at a particular sequence
(area of Bases)
• They are INCREDIBLY accurate, they will ONLY cut the
area that they recognize
• This amazing ability allows us to cut DNA into
fragments so that we can isolate it, separate it,
and/or analyze it.
Restriction Enzyme
• A restriction enzyme is an enzyme that cuts
double-stranded DNA at a specific recognition
nucleotide sequences (A, T, C, G) known as
restriction sites.
• Such enzymes, found in bacteria, are thought to
have evolved to provide a defense mechanism
against invading viruses.
• Restriction enzymes are required when removing
or replacing genes
• They are also very important in the creation of
recombinant DNA
Genetic Engineering Techniques
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Restriction Enzymes
DNA Recombination
DNA Insertion
DNA Sequencing
Transgenic Bacteria, Plants, and Animals
Cloning
Gel electrophoresis
Genetic Engineering Techniques
• DNA RECOMBINANT:
– Literally means “combined DNA”
• DNA fragments cannot function all by
themselves.
• They must be part of the genetic material of
living things cells before the genes they
contain can be activated.
• In this, second step of genetic engineering,
the DNA fragment must be put into a hosts
cells
Genetic Engineering Techniques
• DNA RECOMBINANTS:
– DNA fragments (cut by restriction enzymes) may
be combined with bacterial DNA so that they can
later be inserted into a bacterial cell
– The small, circular DNA molecules in bacteria
(called plasmids) can be removed and cut with a
restriction enzyme.
– The cut ends are sticky to the foreign fragment,
and can allow for the formation of a recombinant
DNA molecule
DNA Recombination
• DNA recombination is sometimes called gene
splicing, because the genes are “cut & pasted”
• The new DNA strand created is considered to be
artificial, because it would not normally occur in
nature
– Benefit of all life using the exact same DNA
• Not the same thing as “natural” genetic
recombination
• This how we engineer drugs to combat bacterial
resistance (like MRSA) and how we are able to
make non-human organisms make things like
human insulin
Genetic Engineering Techniques
• DNA INSERTION:
– During the first 2 steps of genetic
engineering, DNA fragments containing the
desired gene are obtained and then
inserted into DNA that has been removed
from the recipient cell (the cell where the
DNA is going.)
• Forming recombinant DNA (New DNA)
DNA Insertion & Cloning
– To insert the DNA into LIVING cells it is easiest to
use bacteria
• Bacteria in a solution of salt and the desired
DNA will eventually take up the DNA in its own
DNA.
–This is considered DNA insertion
• These new bacteria are then cultured (grown)
into a large colony.
• The technical term for a large number of cells
grown from a single cells Clone.
– So this is DNA cloning.
• You don’t HAVE to use bacteria but it is the
easiest.
Genetic Engineering Techniques
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Restriction Enzymes
DNA Recombination
DNA Insertion
DNA Sequencing
Transgenic Bacteria, Plants, and Animals
Cloning
Gel electrophoresis
Genetic Engineering Techniques
DNA sequencing:
– Sequencing DNA is when you read the nitrogenous bases
(ATCG) along the length of the DNA fragment.
– Only one strand of the double helix is used to sequence
the DNA
• need multiples of the used strand (So you clone it)
– The DNA’s bases are tagged using different chemical
treatments that break the pieces and reveal the Base
sequence.
– By tagging the bases, we are able see the order of A, T, C,
& G and are then able to read the base sequence
Genetic Engineering Techniques
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•
•
•
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Restriction Enzymes
DNA Recombination
DNA Insertion
DNA Sequencing
Transgenic Bacteria, Plants, and Animals
Cloning
Gel electrophoresis
Gel electrophoresis
• During gel electrophoresis, DNA is cut with a
restriction enzyme into small pieces
• Because DNA has a slight negative charge,
different charges are placed at either end of a
gel containing tray.
• When the DNA is placed into the tray it will
slowly move across the gel (towards the +)
• Because the pieces are different sizes they
move at different speeds (large = slower).
DNA Fingerprinting
• The amazing complexity of the human
genome ensures that NO TWO INDIVIDUALS
are exactly the same.
• This biological theory allows for a powerful
new tool in criminal investigations
• Now, finding bodily fluids and/or skin cells at
the scene of a crime or on a victim can link a
suspect to a crime with amazing reliability.
Electrophoresis
Electrophoresis
Genetic Engineering Techniques
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Restriction Enzymes
DNA Recombination
DNA Insertion
DNA Sequencing
Transgenic Bacteria, Plants, and Animals
Cloning
Gel electrophoresis
Genetic Engineering Techniques
• Transgenic (means gene from across species)
– It is now possible to insert genes from one
organism into another.
– Organisms that contain such foreign genes are
said to be Transgenic.
– Trans- across or moved genes
– Requires many of the already mentioned genetic
engineering techniques (most of them)
– This allows us to create organisms with foreign
traits
This transgenic animal is the result of
placing jellyfish genes in an albino rabbit,
and then bathing it in UV light
Transgenic Plants
• It is through the process of genetic
engineering that we have most of the plants
that we use for food.
• Not only can we selectively breed more
productive organisms, but we can use
transgenic organisms to make plants that are
resistant to diseases, insects, drought, winds,
etc.