Biotechnology

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Biotechnology
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Selective Breeding

• This is the oldest type of genetic manipulation.
  
• Breeding organisms for a desired characteristic
• Also known as artificial selection
• Used by farmers to improve the quality of plants
  and animals

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Inbreeding

• Breeding organisms with specific characteristics
  generation after generation
• recessive traits can surface that are harmful
• Pure bred dogs are inbred

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Genetic engineering

• Definition The manipulation of genes for
  practical purposes.
• Genetic engineering, GE, involves building
  recombinant DNA- DNA made from two or more
  different organisms.

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Insulin model

• Used to show the steps involved in the process of
  genetic engineering
• The human gene for insulin production is
  transferred into bacteria.
• Because the genetic code is universal the
  transgenic bacteria transcribes and translates
  the human insulin gene and produces human insulin.

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Steps in a genetic engineering experiment

• Cutting DNA - first, DNA must be extracted and
  cut into pieces
• Making Recombinant DNA
• Cloning
• Screening

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Step 1- Cutting DNA

• (bacterial) Restriction enzymes recognize and
  bind to short sequences of DNA
• Each restriction enzyme cuts between specific
  nucleotides
• A vector is used to carry the gene of interest
  into another cell. Commonly used vectors are
  plasmids, viruses, yeast
• Plasmids are circular DNA within bacteria that
  replicate independently of the main chromosome

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Step 2- Making Recombinant DNA

• DNA fragments from the organism of interest are
  combined with the DNA fragments of the vector
• DNA ligase, an enzyme, helps bond the two together

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Another example of recombinant DNA
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Step 3 - Cloning

• Gene cloning occurs when many copies of the gene
  of interest are formed as the host organism
  undergoes binary fission and replicates

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Step 4 Screening cells

• Cells that did not pick up the vector are
  separated from those that did
• Only the cells that contain the vector are
  resistant to the antibiotic tetracycline and
  survive when the antibiotic is added
• The surviving cells multiply and form genetically
  identical cells or clones
• How does the scientist know which cells picked up
  the vector?

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Southern Blot

• This technique is used to test the presence of
  the gene of interest in the cloned colonies.
• The DNA from each clone colony is cut by
  restriction enzymes
• The DNA is separated by electrophoresis a
  process where an electrical field separates
  macromolecules by their size and charge.
• DNA is negatively charged and migrates through
  the gel towards the positive pole. The smallest
  DNA fragments move the fastest and a banded
  pattern results
• The DNA bands are transferred blotted- onto
  filter paper with a probe of radioactive or
  fluorescent RNA or single strand DNA with the
  complementary nucleotides.
• only those DNA fragments complementary to the
  probe will show up as a visible band.

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Gel Electrophoresis

• Basic materials needed include a power supply,
  gel bed.

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Genetic Engineering in medicine and society

• Medicines - Many genetic disorders are caused by
  the body not making important proteins. G.E.
  techniques can produce products such as
  anticoagulants that dissolve blood clots,
  insulin, and proteins that promote blood clotting
  that are used by hemophiliacs

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Uses of GE

• Vaccines normally a vaccine, weakened form of a
  disease causing agent are made by killing a
  pathogen or by making the microbe unable to grow.
  But there is still a slim chance that it might
  cause the disease. By using GE, a harmless
  bacteria that has the genes that encode for the
  surface proteins of the pathogen can be inserted
  and become a safe vaccine

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More uses

• DNA fingerprinting to solve crimes, establish
  paternity or maternity, archaeology, well
  preserved fossils
• Gene therapy is a promising way to cure genetic
  disorders- putting healthy copy of a gene into
  the cells of an individual whose cells are
  defective.
• Cystic fibrosis, cancer, hemophilia and others
  are being treated

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PCR

• Often only very small amounts of DNA are found at
  a crime scene. PCR polymerase chain reaction
  is a method used to make many copies of the
  desired DNA sample
• Samples are heated which separates the DNA
  strands
• They are cooled and primers are added (short
  pieces of artificially made DNA that bind where a
  copy can be made.
• Free nucleotides are added and new strands form

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DNA fingerprinting

• A pattern of dark bands on photographic film that
  is made when an individuals DNA fragments are
  separated by gel electrophoresis.
• Since each individual has unique DNA restriction
  enzymes cut the DNA from different individuals to
  different lengths hence each will have a unique
  pattern or DNA fingerprint

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Practical Applications

• Criminal Identification Forensics DNA
  isolated from blood, hair, skin cells or other
  genetic evidence can be compared through the
  comparison of patterns with the DNA of a suspect

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Human Genome Project

• A project whose goal was to determine the entire
  nucleotide sequence of the entire human genome
  and to map the location of all genes. 2003
• Genome all of an organisms DNA
• Human genome has 23 pairs of chromosomes, about 3
  million nucleotide bases and about 20-30,00 genes
• Many segments of genes of genetic disorders have
  been identified.
• Many organisms completed E. coli, Drosophila, C.
  Elegans, Yeast, Mice, Dog, human.

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GE in Agriculture

• Prior to GE, plant breeders only used the
  principles of genetics to produce improved plants
• GE can change plants often called GMO,
  genetically modified organisms, or transgenic
  organisms to develop plants to be
• more tolerant to drought or salty soils etc.
• Improve plants nutrition by adding vitamin A
• Development of crops resistant to glyphosate, a
  weed killer the weeds can be killed leaving the
  cash crops healthy.
• Bt plants plants with a gene from Bacillus
  theringiensis make them resistant to insects
  that would chew them, reducing the amount of
  insecticides applied.

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Genetically modified food
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Genetically modified animals

• Increase milk production, produces more milk with
  fewer cows, at less cost to farmer and consumer
• Growth hormone to increase size of cattle and cows

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Transgenic Organisms those with foreign DNA

• The gene that makes fireflies glow has been added
  to this plant it actually glows in the dark as
  does the transgenic cat

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Cloning

• Clone member of a population of identical cells
  produced from a single cell
• Embryo cloning coaxing an individual cell to
  split as it can with identical twins naturally
• Therapeutic cloning cloning an adults DNA in
  hopes of creating tissues or organs the person
  can use
• Reproductive cloning cloning of an adults DNA
  in hopes of creating a genetically identical
  individual which can grow to adulthood
• Used to produce herds of animals to make useful
  proteins

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Reproductive Clone

• Take an egg cell (stem cell)
• Remove the nucleus
• Add genetic material from another adult cell
• Allow the cell to divide
• The embryo is placed in a foster mother like in
  vitro fertilization to grow and be born naturally

CBC News
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Stem Cells

• Definition Undifferentiated cells that give rise
  to other types of cells
• Have the ability to change into other types of
  cells (specialized)
• Needed for both reproductive and therapeutic
  cloning
• Potential to treat many diseases, including
  Parkinson's, Alzheimer's, diabetes and cancer.
• May also be used to regenerate organs

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Types of Stem Cells

• Embryonic stem cells - Stem cells taken from
  human embryos. Potential to become any type of
  cell (pluripotent).
• Fetal stem cells- Stem cells taken from aborted
  fetal tissue. These may not be as pluripotent
  as embryonic stem cells because they are further
  along in development.
• Umbilical or baby teeth stem cells - Stem cells
  take from umbilical cords and baby teeth. These
  are younger than adult stem cells and can
  divide more times.
• Adult stem cells Commonly taken from bone marrow

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Blastocyst 64-128 cells
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How it works

• Stem cells are injected into the area of the body
  being targeted for tissue regeneration
• As the stem cells come into contact with growth
  chemicals in the body, the chemicals program the
  stem cells to grow into the tissue surrounding
  it.