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DNA Technology

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Genetic Engineering

• Using technology to Using technology to manipulate the DNA of manipulate the DNA of one organism by one organism by inserting DNA of inserting DNA of another organismanother organism

• Used for studying a Used for studying a particular gene, particular gene, disease, or traitdisease, or trait

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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

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Cutting DNACutting DNA• Restriction enzymesRestriction enzymes cut

DNA at specific sequences•Useful to divide DNA into

manageable fragmentsmanageable fragments

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Restriction EnzymesRestriction Enzymes• The cut can be made The cut can be made

straight across a straight across a base-pair sequence base-pair sequence resulting - "resulting - "Blunt EndBlunt End““

• The cut can be made The cut can be made in an offset manner in an offset manner leaving exposed leaving exposed nucleotide sequences. nucleotide sequences. These exposed These exposed sequences are called sequences are called ""Sticky EndsSticky Ends""

Blunt EndBlunt End

Sticky endSticky end

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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

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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

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Electrophoresis

•DNA can be separated based on size and chargesize and charge

•The phosphate phosphate groupsgroups are negativelynegatively charged

•DNA is placed in a gelgel and electricityelectricity is run through

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Electrophoresis

• Negative DNANegative DNA moves toward the positive end

• SmallerSmaller fragments move farther and fasterfarther and faster

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Electrophoresis

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DNA FingerprintingDNA Fingerprinting*Structural genes are often separated by *Structural genes are often separated by large regions of repeating base pairs (junk large regions of repeating base pairs (junk DNA)DNA)*The number of these repeats is unique to *The number of these repeats is unique to an individual.an individual.*When DNA from a person is cut with a *When DNA from a person is cut with a restriction enzyme, the length of the restriction enzyme, the length of the fragments will be unique to an individual.fragments will be unique to an individual.

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DNA Fingerprinting Contd…DNA Fingerprinting Contd…*This will produce a *This will produce a

unique banding unique banding pattern when run on pattern when run on gel electrophoresis.gel electrophoresis.

*This test is highly *This test is highly accurate, and the accurate, and the probability of probability of another individual another individual possessing an possessing an identical banding identical banding pattern is estimated pattern is estimated as around as around 1:14,000,000,0001:14,000,000,000. .

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DNA FingerprintingDNA Fingerprinting

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Copying DNACopying DNA• Polymerase Chain ReactionPolymerase Chain Reaction• Also called PCR • A method of making many copies

of a piece of DNA

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PCRPCR

Large amounts of DNA can be Large amounts of DNA can be made from a small starting made from a small starting

samplesample

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CloningCloning• CloneClone- a

member of a group of genetically identical cells

• May be produced by asexual asexual reproductionreproduction (mitosis)

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Cloning Cloning organismsorganisms

• A body cellbody cell from one organism and an egg cellegg cell from another are fused

• The resulting cell divides divides like a normal embryolike a normal embryo

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Cloning “Dolly”Cloning “Dolly”

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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

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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

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Human Genome Human Genome ProjectProject

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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

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HGP InsightsHGP 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)

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Benefits of Human Genome Project

• Improvements in Improvements in medical medical preventionprevention of disease, gene of disease, gene therapies, diagnosis therapies, diagnosis techniques …techniques …

• Production of useful proteinProduction of useful protein products for use in medicine, products for use in medicine, agriculture, bioremediation agriculture, bioremediation and pharmaceutical industries.and pharmaceutical industries.

• Improved Improved bioinformaticsbioinformatics – – using computers to help in using computers to help in DNA sequencing …DNA sequencing …

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Benefits of Genetic Benefits of Genetic EngineeringEngineering

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Biotechnology -Biotechnology -Biotechnology -Biotechnology -

• The use of gene science to create new products from plants and animals

• The use of gene science to create new products from plants and animals

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BiotechnologyProvides:BiotechnologyProvides:

• Improved food products

•Medical advances

• An enhanced environment

• Improved food products

•Medical advances

• An enhanced environment

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Herbicide Resistant Crops

• Soybeans: Roundup Ready• Corn: Roundup Ready, Liberty Link • Cotton: BXN, Roundup Ready • Canola: Liberty Link, Roundup Ready

+ CP4 EPSPS = Roundup gene Ready

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Biotechnology BreakthroughsBiotechnology Breakthroughs• Insulin (1982)

– First commercial biotech product– Reliable, inexpensive source of

insulin

• Rice– Enriched with beta-carotene and iron

• Bananas– Containing edible hepatitis vaccine

• Insulin (1982)– First commercial biotech product– Reliable, inexpensive source of

insulin

• Rice– Enriched with beta-carotene and iron

• Bananas– Containing edible hepatitis vaccine

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Biotechnology BreakthroughsBiotechnology Breakthroughs

• Potatoes with higher solid content

• Garlic that lowers cholesterol

• Fruits and vegetables that reduce risks of cancer and heart disease

• Potatoes with higher solid content

• Garlic that lowers cholesterol

• Fruits and vegetables that reduce risks of cancer and heart disease

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Environmental Benefits

Environmental Benefits

•Reduced pesticide use

•Lower energy requirements

•Cleaner water

•Less soil erosion

•Reduced pesticide use

•Lower energy requirements

•Cleaner water

•Less soil erosion

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