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Chapter 9: Biotechnology
9.1, 9.3, & 9.4
9.1: Manipulating DNA
 Key Concept:
 Biotechnology relies on cutting DNA at specific places.
Scientists use several techniques to
manipulate DNA.
 Chemicals, computers, and bacteria are used to
work with DNA.
 Scientists use these tools in genetics research
and biotechnology.
Restriction enzymes
 Collected from bacteria
 Used for cutting DNA to isolate specific gene or
genes
 Cut DNA at specific nucleotide sequences called
restriction sites.
 Can leave blunt ends (straight cuts) or sticky ends
(staggered cuts with free nucleotides)
 Cut DNA can be used to study gene sequence or
placed into the DNA of another organism.
Restriction sites
Restriction maps show the lengths of
DNA fragments.
 Gel electrophoresis is used to
separate DNA fragments by size.
 A DNA sample is cut into fragments
with restriction enzymes.
 Electrical current pulls DNA
fragments through a gel.
 Smaller fragments move faster
and travel farther than larger
fragments.
 Fragments of different sizes
appear as bands on the gel
 A restriction map shows the
lengths of DNA fragments
between restriction sites.
 Only indicate size, not
DNA sequence
 Useful in genetic
engineering, studying
mutations (may change lengths of
fragments), or for DNA fingerprinting.
9.3: DNA Fingerprinting
 Key Concept:
 DNA fingerprints identify people at the molecular
level
A DNA fingerprint is a type of restriction map.
 DNA fingerprints are based on parts of an individual’s
DNA that can be used for identification
 Based on noncoding regions of DNA
 Noncoding regions have repeating DNA sequences
 Number of repeats differs between people
 Banding pattern on a gel is a DNA fingerprint
DNA fingerprinting is used for identification.
 DNA fingerprinting depends on the probability of a
match.
 Many people have the same number of repeats in a
certain region of DNA
 The probability that two people share identical
numbers of repeats in several locations is very small
(only one chance in 1 billion-10 billion people that
they would match)
 Several regions of DNA are used to make a DNA
fingerprint to make it more likely the fingerprint is
unique.
(mother) (child 1) (child 2) (father)
Uses of DNA Fingerprinting
 Forensics: evidence in criminal cases
 Paternity tests
 Immigration requests
 Positive identification
 Studying biodiversity
 Tracking genetically modified crops
 http://www.youtube.com/watch?v=PSwlCk_Z02c
9.4: Genetic Engineering
 Key Concept:
 DNA sequences of organisms can be changed.
Genetic Engineering
 Involves changing an organism’s DNA to give it new
traits
 Based on the use of recombinant DNA
 Recombinant DNA contains DNA from more than
one organism
 Gene splicing involves cutting the gene from one
organism and pasting it into another organism’s
DNA to give it the trait coded for by that gene
(makes recombinant DNA)
 Bacteria frequently used in genetic engineering because they
have plasmids – closed loops of DNA.
(bacterial DNA)
Genetic engineering produces organisms
with new traits.
 Gene splicing involves cutting the gene from one
organism and pasting it into another organism’s DNA to
give it the trait coded for by that gene.
 Restriction enzymes cut plasmid and foreign DNA
 Foreign gene inserted into plasmid
Restriction Enzyme Clip
 http://www.youtube.com/watch?v=lskM09vOn_M
Uses of Genetic Engineering
 Medicine: Transgenic bacteria can be used to produce human
proteins
 Bacteria can be used to produce human insulin for diabetics
 Provides a steady, inexpensive supply.
 Transgenic plants are common in agriculture
 transgenic bacteria infect a plant
 plant expresses foreign gene
 many crops are now genetically modified
(GMO)
 Gives them traits like resistance to frost, diseases, insects
 Increase crop yield – more food quickly and cheaply
 Increase nutrient levels in crops like rice.
 Transgenic animals are used to study diseases and gene functions
Concerns about Genetic Engineering
 Possible long-term health effects of eating GM foods.
 Allergies?
 Possible effects of GM plants on ecosystems and biodiversity
 Lack of genetic diversity in transgenic plants could leave them
vulnerable to new diseases or pests.
 Effects on natural plant pollinators like bees and butterflies.
 Cross pollination between transgenic plants and natural plants.
Cloning
 A clone is a genetically identical copy of a gene or an
organism
 Cloning occurs in nature
 Bacteria (binary fission)
 Some plants (from roots)
 Some simple animals (budding, regeneration)
Cloning mammals
 Process called nuclear transfer
 Nucleus is removed from an egg cell
 Nucleus from a cell from the animal to be cloned is
implanted in the egg
http://www.youtube.com/watch?v=Qry1gYYDCA
Pros/Cons of Cloning
Benefits
 Organs for transplant
into humans
 Save endangered
species
Concerns
 Low success rate
 Clones “imperfect” and
less healthy than original
animal
 Decreased biodiversity
9.5 & 9.6 Genomics & Gene
Therapy
Genomics: Is the study of genomes (all of an organisms
DNA)
• This has provided a big step in understanding evolution.
The Human Genome Project: (2003) scientists mapped and
sequenced all of the DNA from a few humans to figure out
our common base pairs of the entire set of chromosomes.
http://www.youtube.com/watch?v=N4i6lYfYQzY
• Gene Therapy: the replacement of a defective or
missing gene, or the addition of a new gene into a
person's genome to treat a disease.
http://www.youtube.com/watch?v=bLI1Gfb0ynw
• This is a promising treatment option for inherited
genetic disorders & certain types of cancers, but it
is still in the experimental phase.