Download DNA Lab Techniques

DNA
Technology
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DNA Extraction
• Chemical treatments cause
cells and nuclei to burst
• The DNA is inherently
sticky, and can be pulled
out of the mixture
• This is called “spooling”
DNA
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“Spooled” DNA
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Cutting DNA
• Restriction enzymes cut
DNA at specific sequences
• Useful to divide DNA into
manageable fragments
4
Electrophoresis
• DNA can be
separated based on
size and charge
• The phosphate
groups are negatively
charged
• DNA is placed in a
gel and electricity is
run through
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Electrophoresis
• Negative DNA moves toward
the positive end
• Smaller fragments move
farther and faster
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Electrophoresis
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Steps in DNA Sequencing
• Many copies of a single
strand of DNA are placed in
a test tube
• DNA polymerase is added
• A mixture of nucleotides is
added some of which have
dye molecules attached
• Each base (A,T,C,G) has a
different color dye
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Steps in DNA Sequencing
• By chance, some dyed
nucleotides & some
regular ones are added
• Dye molecules are large
and stop the chain from
growing
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DNA
Sequencing
• The result is
DNA fragments
of multiple
sizes with
colors that can
be identified
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DNA Sequencing
• After the gel separates
the resulting fragments
by size, we 'read' the
sequence from bottom to
top.
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Copying DNA
• Polymerase Chain Reaction
• Also called PCR
• A method of making many
copies of a piece of DNA
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Steps in Copying DNA
• A DNA molecule is placed in
a small test tube
• DNA polymerase that can
work at high temps is
added
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Steps in Copying DNA
• The DNA is heated to
separate the two
strands
• Primers, short pieces of
DNA complementary to
the ends of the
molecule to be copied,
are added
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Copying DNA
• The tube is cooled, and
DNA polymerase adds new
bases to the separated
strands
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PCR
Large amounts of DNA can be made
from a small starting sample
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Cloning
• Clone- a member
of a group of
genetically
identical cells
• May be produced
by asexual
reproduction
(mitosis)
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Cloning organisms
• A body cell from one
organism and an egg cell
from another are fused
• The resulting cell divides
like a normal embryo
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Cloning “Dolly”
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Human Genome
Project
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Human Genome Project
• Started in 1990
• Research effort to sequence
all of our DNA (46
chromosomes)
• Over 3.3 billion nucleotides
• Mapping every gene location
(loci)
• Conducted by scientists
around the world
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HGP Insights
• Only 2% of human genome codes for
proteins (exons)
• Other 98% (introns) are non-coding
• Only about 20,000 to 25,000 genes
(expected 100,000)
• Proteome – organism’s complete set of
proteins
• About 8 million single nucleotide
polymorphisms (SNP) – places where
humans differ by a single nucleotide
• About ½ of genome comes from
transposons (pieces of DNA that move
to different locations on chromosomes)
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Benefits of Human
Genome Project
• Improvements in medical
prevention of disease, gene
therapies, diagnosis techniques …
• Production of useful protein
products for use in medicine,
agriculture, bioremediation and
pharmaceutical industries.
• Improved bioinformatics – using
computers to help in DNA
sequencing …
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Benefits of Genetic
Engineering
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Biotechnology •
The use of gene
science to create new
products from plants
and animals
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Biotechnology
Provides:
• Improved food products
• Medical advances
• An enhanced environment
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Herbicide Resistant
Crops
+ CP4 EPSPS = Roundup
gene
Ready
•
•
•
•
Soybeans:
Corn:
Cotton:
Canola:
Roundup Ready
Roundup Ready, Liberty Link
BXN, Roundup Ready
Liberty Link, Roundup Ready
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Biotechnology Breakthroughs
• Insulin (1982)
– First commercial biotech
product
– Reliable, inexpensive source of
insulin
• Rice
– Enriched with beta-carotene
and iron
• Bananas
– Containing edible hepatitis
vaccine
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Biotechnology Breakthroughs
• Potatoes with higher solid
content
• Garlic that lowers cholesterol
• Fruits and vegetables that
reduce risks of cancer and
heart disease
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Environmental Benefits
• Reduced pesticide use
• Lower energy requirements
• Cleaner water
• Less soil erosion
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