Transcript Frontiers of Biotechnology Chapter 9 Mr. Scott Manipulating DNA • How can scientists manipulate the code? • Scientists use their knowledge of the structure of DNA and its chemical properties to.

Frontiers of
Biotechnology
Chapter 9
Mr. Scott
Manipulating DNA
• How can scientists
manipulate the code?
• Scientists use their
knowledge of the
structure of DNA and
its chemical properties
to study and change
DNA molecules.
Manipulating DNA
• Tools of Molecular
Biology
– Genetic Engineering
• Making changes in the
DNA code of a living
organism
– DNA Extraction
• Open a cell (mechanical
and chemical methods)
• Use a chemical to separate
the DNA from the rest of
the cell parts (an alcohol)
Manipulating DNA
– Cutting DNA
• DNA molecules are very
long
• Restriction enzymes
– Enzymes that cuts DNA
at a specific sequence of
nucleotides
• Restriction Site
– Site where restriction
enzyme cuts DNA
• Hundreds of different
restriction sites from
enzymes
Manipulating DNA
• Sticky ends –
these are the cut
ends of the DNA
– Pieces can stick
to corresponding
nucleotides
– Used in
biotechnology
Manipulating DNA
– Separating DNA
• Gel electrophoresis
– A mixture of DNA
fragments is placed at
one end of a porous
gel (negative end), and
an electric voltage is
applied to the gel
– The molecules will
move from negative
to positive
Manipulating DNA
• Restriction
Maps
– A pattern of
bands showing
lengths of cut
DNA
– Can be used to
study mutations
Manipulating DNA
Copying DNA
• PCR or Polymerase
chain reaction
• Photocopying DNA
over and over
• Use strands of DNA
that are called
primers
Copying DNA
3 – Step Process
•
–
Need DNA to be
copied, 4 bases,
and two primers
•
Primers – short
segment of used
for starting point
Steps
•
1.
2.
3.
Separating
Binding
Copying
DNA Fingerprinting
• DNA
Fingerprinting
– DNA that can be
used for
identification
– Cut with enzyme
and run through
gel electrophoresis
DNA Fingerprinting
• Greatest differences in DNA are
found in regions not used for
genes
–Each person has differing numbers
of repeating units in similar regions
–Differences are found by gel
electrophoresis
DNA Fingerprinting
• Indentification
and Probability
– Identification
depends on
probability
DNA Fingerprinting
• Uses of
Fingerprinting
– Criminal cases
– Family relations
• Paternity
• Kinship for
immigration
purposes
• Species studies
• Agriculture
Genetic Engineering
• Cloning
– Clone – a genetically
identical model
• Gene or organism
– Transfer DNA
between cells
– Dolly – The cloned
sheep from 1997
– Controversial
Genetic Engineering
• Cloning has potential benefits.
– organs for transplant into humans
– save endangered species
• Cloning raises concerns.
– low success rate
– clones “imperfect” and less healthy than
original animal
– decreased biodiversity
Genetic Engineering
• Genetic
Engineering
– Changing DNA
to give it new
traits
– Can insert
healthy genes or
cloned genes
Manipulating DNA
– Cutting and Pasting
• Recombinant DNA
• Enzymes join genes
from one strand of
DNA with genes
from another strand
of DNA
• DNA synthesizers
– Enzymes join artificial
pieces of DNA with
natural pieces
Genetic Engineering
• Transforming Bacteria
– Foreign DNA is joined
to plasmid
• Plasmid – small, circular
DNA molecule
• Genetic marker – a gene
that makes it possible see
which bacteria are
carrying the plasmid (that
is marked) and which
bacteria are not.
Genetic Engineering
• Transformation
– When a cell takes
in foreign DNA
and joins it with
the existing
DNA
– This external
DNA becomes
part of the cells
DNA
Genetic Engineering
• New genes can be
added to an organism’s
DNA.
– Genetic engineering
involves changing an
organism’s DNA to
give it new traits.
– Genetic engineering is
based on the use of
recombinant DNA.
– Recombinant DNA
contains genes from
more than one
organism.
(bacterial DNA)
Genetic Engineering
• Transgenic Organisms
– Organisms that contain
genes from other species
– Firefly and tobacco
plant
– Genetic engineering has
increased the growth of
biotechnology
Genetic Engineering
• Transforming Plant Cells
– Using bacterium that
normally infect plant cells
and cause tumors
– Taking away the cell wall
some plant cells will take
up DNA on their own
– If successful recombinant
DNA will be found in a
chromosome of the cell
Genetic Engineering
• Transforming Animal
Cells
– DNA can be injected
directly into the
nucleus of an egg
– Enzymes help insert
the new DNA into the
eggs existing DNA
– New DNA contains
markers that tell which
cells picked up the
DNA
Genetic Engineering
– Transgenic
microorganisms
• Bacteria reproduce
quickly
• Uses:
– Can grow human
proteins
• Insulin, growth
hormone, and
clotting factor
Genetic Engineering
– Transgenic Animals
• Mimic human body for
testing
• Faster growing animals
• No more food poisoning
• Grow human proteins
Genetic Engineering
• Transgenic animals
are used to study
diseases and gene
functions.
– Transgenic mice used
to study development
and disease
– Gene knockout mice
used to study gene
function
• Leptin – helps control
food intake –
common for the obese
Genetic Engineering
Genetic Engineering
– Transgenic Plants
• Natural insecticide
• Resist weed killing
chemicals
• Food resistant to
spoiling
• Weather resistant plants
• Grow vitamins or
proteins
Genomics and Bioinformatics
• Genomics is the study of
genomes.
–Can include the sequencing of the
genome
–Comparisons of genomes within and
across species
Genomics and Bioinformatics
• DNA Sequencing
– Determining the
order of DNA
nucleotides in
genes or in
genomes.
– Genomes of
several different
organisms have
been sequenced
Genomics and Bioinformatics
• The Human Genome
Project
– Has sequenced all of
the DNA base pairs
of human
chromosomes.
– Analyzed DNA from
a few people
– Still working to
identify and map
human genes
Genomics and Bioinformatics
• Technology and Genes
– Bioinformatics
• The use of computer
databases to organize
and analyze biological
data.
– DNA microarrays
• Used to study the
expression of many
genes at once.
– Proteomics
– The study and
comparison of
proteins.
Genetic Screening and
Therapy
• Genetic screening can detect genetic disorders.
– Determines risk of having
or passing on a genetic
disorder
– Used to detect specific
genes or proteins
– Can detect some genes
related to an increased
risk of cancer
– Can detect some genes
known to cause genetic
disorders
DMD
N
Genetic Screening and
Therapy
• Gene therapy is the replacement of
faulty genes.
• Several experimental techniques are
used for gene therapy.
– Genetically engineered viruses used to
“infect” a patient’s cells
– Insert gene to stimulate immune system to
attack cancer cells
– Insert “suicide” genes into cancer cells
that activate a drug
Genetic Screening and
Therapy
• Gene therapy has many technical
challenges.
–Inserting gene into correct cells
–Controlling gene expression
–Determining effect on other genes