Download DNA Technology

DNA
Technology
1
Genetic Engineering
• Using technology to
manipulate the DNA of
one organism by inserting
DNA of another organism
• Used for studying a
particular gene, disease,
or trait
2
Recombinant DNA
• Combining fragments of DNA
from one source with
fragments of DNA from
another source
• Usually involve the use of
bacteria cells as the host
– Plasmids – small, circular pieces
of DNA in bacteria
3
Cutting DNA
• Restriction enzymes cut
DNA at specific sequences
• Useful to divide DNA into
manageable fragments
4
Restriction Enzymes
• The cut can be made
straight across a
base-pair sequence
resulting - "Blunt End“
• The cut can be made
in an offset manner
leaving exposed
nucleotide sequences.
These exposed
sequences are called
"Sticky Ends"
Blunt End
Sticky end
5
Recombinant DNA
Process
1. Cut plasmid and DNA
fragment from organism of
choice with the same
restriction enzyme
2. Join plasmid with DNA
fragment using the enzyme
DNA ligase (recombination)
3. Insert transformed plasmid
back into bacteria cell
6
Recombinant DNA
Process
4. Bacteria molecules containing
recombinant DNA grow
making many copies of
identical bacteria (cloning)
5. Isolate the gene copied in the
bacteria
7
8
9
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
10
Electrophoresis
• Negative DNA moves toward
the positive end
• Smaller fragments move
farther and faster
11
Electrophoresis
12
DNA Fingerprinting
*Structural genes are often separated by large
regions of repeating base pairs (junk DNA)
*The number of these repeats is unique to an
individual.
*When DNA from a person is cut with a
restriction enzyme, the length of the
fragments will be unique to an individual.
13
DNA Fingerprinting Contd…
*This will produce a
unique banding
pattern when run on
gel electrophoresis.
*This test is highly
accurate, and the
probability of another
individual possessing
an identical banding
pattern is estimated
as around
1:14,000,000,000.
14
DNA Fingerprinting
15
Copying DNA
• Polymerase Chain Reaction
• Also called PCR
• A method of making many
copies of a piece of DNA
16
PCR
Large amounts of DNA can be made
from a small starting sample
17
Cloning
• Clone- a member
of a group of
genetically
identical cells
• May be produced
by asexual
reproduction
(mitosis)
18
Cloning organisms
• A body cell from one
organism and an egg cell
from another are fused
• The resulting cell divides
like a normal embryo
19
Cloning “Dolly”
20
21
Stem Cells
• A human embryo up to 14 days
is a ball of undifferentiated
cells called stem cells
• They have the potential to
develop into various types of
cells
22
Stem Cells
• As an adult, you have some
stem cells (bone marrow), but
they can only develop into
certain types of tissue
• Embryonic stem cells have the
potential to help people with
disabling diseases that affect
tissues
23
Human Genome
Project
24
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
25
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)
26
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 …
27
Benefits of Genetic
Engineering
28
Biotechnology •
The use of gene
science to create new
products from plants
and animals
29
Biotechnology
Provides:
• Improved food products
• Medical advances
• An enhanced environment
30
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
31
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
32
Biotechnology Breakthroughs
• Potatoes with higher solid
content
• Garlic that lowers cholesterol
• Fruits and vegetables that
reduce risks of cancer and
heart disease
33
Environmental Benefits
• Reduced pesticide use
• Lower energy requirements
• Cleaner water
• Less soil erosion
34
35