Transcript Forensic Uses

Arrangements
Forensic uses
• DNA profiling:
– relies on repetitive,
– hypervariable DNA and not genes per se.
• Stages involved:
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DNA isolation,
restriction enzyme digestion,
gel electrophoresis,
blotting DNA onto a filter,
hybridisation with a probe.
• Use of single locus probe.
Learning Objective
• To explain how DNA technology has
been adapted foe use by forensic
scientists.
Forensic Uses
• Out with the old
– DNA fingerprinting
• In with the new
– DNA profiling
• A sample of DNA from a suspect can be
matched with that of a reference sample.
• PCR is used to amplify minute samples of
DNA
DNA profiling
• Uses minisatellite regions
– Variable number tandem repeats
(VNTRs)
• Steps
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DNA isolation,
restriction enzyme digestion,
gel electrophoresis,
blotting DNA onto a filter,
hybridisation with a probe
Probes
• Binds to a specific base sequence on
target fragments
– Multi-locus probes
• More complex patterns
– Single locus probes
DNA profiling
• Short tandem repeats (STRs)
– A.k.a. microsatellites
– PCR based technique
• Uses fluorescent labels and
automated DNA detection equipment.
Arrangements
Agriculture - Transgenic plants
• Transgenic plants are engineered by using a
plasmid from Agrobacterium.
– Foreign DNA carrying genes for the desired
characteristics inserted into bacterial plasmid.
– Plant cell protoplasts incubated with bacteria
containing genetically engineered plasmid in
medium which allows only those plant cells which
have taken up the foreign DNA to grow.
– Illustrate application by transgenic tomato
plants:
• gene for bacteria toxin transferred to plants
resulting in effective protection from insect
damage.
Arrangements
Agriculture - Transgenic plants
• Moral and ethical issues relating to the use
of transgenics.
Arrangements
Agriculture - BST
• Production of bovine somatotrophin
(BST) by genetic engineering and its
use in cattle.
– Gene for BST cloned into a bacterial
system.
– Product purified and administered to
cattle by injection or in feed.
– BST increases milk production.
Learning Objective
• To describe the production of transgenic or
GM crops
– Explain why a plasmid from Agrobacterium is
used
– Explain how foreign DNA is isolated and
inserted into plasmids
– Explain how plants containing recombinant DNA
can be grown and expanded
– Describe the production of transgenic tomato
plants
• To list some potential uses of GM plant
technology
Learning Objective
• To describe the production of BST
• To describe the use of BST
Keywords - Activity
• Find the meaning of the following
words
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Microinjection
Transfection
Transformation
Transgene
Transgenic
DNA cloning
DNA technology and Agriculture
• Two uses of DNA technology in
agriculture
– Production of Transgenic organisms
• Transgenic plants
– Production of growth hormones using
recombinant DNA methods.
• Bovine growth hormone
Transgenic plants
• Requirements
– Suitable vector
– Mechanism for regenerating whole plants
• Ti Plasmid
– Found in soil bacterium Agrobacterium
tumefaciens (crown gall disease)
Preparation of Ti plasmid
• The Ti plasmid can integrate DNA into
plant cell genome
• Stages
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Remove tumour inducing genes
Insert gene and marker
Culture plasmid and protoplasts
Stimulate cell wall development
Callus formation
Seedling formation
Transgenic plants
• FLAVR SAVR tomato
– Production of ethylene is inhibited to delay the
ripening process.
• Insect resistance
– Insert a gene from Bacillus thuringiensis that
produces an insecticidal protein
• Introduction of nitrogen fixation genes into
non-leguminous plants.
• Disadvantage of Ti-based vector system
– Can only work for dicotyledonous plants
– A lot of crops are monocotyledonous.
Bovine Growth Hormone
bovine somatotrophin (BST)
• BST
– Increases milk yield by 10%
– Improves weight gain in beef cattle by
diverting resources to cell and protein
production, suppresses the production of
fatty deposits.
Learning Objective
• To list potential uses of DNA
technology
• To understand some of the moral and
ethical issues raised by the
production of transgenic plants and
animals.