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DNA Technology

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DNA Extraction

• Chemical treatmentsChemical treatments cause cells and nuclei to burst

•The DNA is inherently stickysticky, and can be pulled out of the mixture

•This is called “spooling”“spooling” DNA

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“Spooled” DNA

Genetic Engineering

•Manipulating a set of genetic changes on an organisms DNA

Double Helix by Nancy Werlin

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Cutting DNACutting DNA• Restriction enzymesRestriction enzymes -cut

DNA at specific sequences

•Enzymes recognize 4-6 nucleotides and cut both strands of DNA ex: EcoR1, Bam1 ….

• Recombinant DNARecombinant DNA – DNA from two sources combined to produce a single DNA molecule

• Useful to divide DNA into manageable fragmentsmanageable fragments

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Restriction Enzymes

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Electrophoresis

• DNA sequences 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 positively charged end of gel plate

• SmallerSmaller fragments move farther and fasterfarther and faster

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Electrophoresis

• What would it mean if there were the same amount of nucleotides in each DNA fragment?

• Where else have we seen different sizes of DNA displayed?

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Karyotypes

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Steps in DNA Steps in DNA SequencingSequencing

• Many Many copiescopies of a single of a single strand of DNA are placed strand of DNA are placed in a test tubein a test tube

• DNA polymeraseDNA polymerase is added is added• A mixture of nucleotides A mixture of nucleotides

is added some of which is added some of which have been treated w/ have been treated w/ radioactive phosphorous radioactive phosphorous dye dye

• Each base (A,T,C,G) has a Each base (A,T,C,G) has a different color dyedifferent color dye

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Steps in DNA Steps in DNA SequencingSequencing

•By chance, some some dyed nucleotidesdyed nucleotides & some some untreateduntreated strandsstrands are added

•Dye molecules are large and stop the stop the chainchain from growing

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DNA DNA SequencingSequencing

•The result is DNA fragments of multiple sizes with colors colors that can be that can be identified identified A,A,G,G,C, C, TT

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DNA SequencingDNA Sequencing

• After the gel After the gel separates the separates the resulting fragments resulting fragments by size, we by size, we 'read' the 'read' the sequence from sequence from bottom to topbottom to top..

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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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Steps in Copying Steps in Copying DNADNA

•A DNA molecule is placed in a small test tube

• DNA polymeraseDNA polymerase that can work at high temps is added

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Steps in Copying Steps in Copying DNADNA

•The DNA DNA is heatedis heated to separate the two strands

• PrimersPrimers, short pieces of DNA complementary to the ends of the molecule to be copied, are added

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Copying DNACopying DNA

•The tube is cooled, and DNA polymerase adds DNA polymerase adds new bases to the new bases to the separated strandsseparated strands

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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

DNA Fingerprinting

• Process that identifies an individuals DNA pattern for their genes, and “junk” repeats between genes.– Exons – code for proteins– Introns – spacers

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• using specific restriction enzymes to cut DNA at points representing the targeted tandem repeat sequences.

• FBI looks at 13 specific repeats to compare between people

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DNA Fingerprint

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CloningCloning• CloneClone- a member

of a group of genetically identical cells grown from a single cell

• 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

2 types

• Reproductive cloning- Dolly

• Therapeutic cloning- Make tissues or organs that are genetically identical to the donor

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Cloning “Dolly”Cloning “Dolly”

Ethics of Cloning

• Should we clone organisms?

• Should we use clones for “spare parts”??

• Will scientists try to design “perfect” people??

• Who should control the use and design of a humans??

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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 –

(gene therapy and genetic screening)

• An enhanced environment

• Improved food products

• Medical advances –

(gene therapy and genetic screening)

• 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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