Biotechnology and Genetic Engineering

Biotechnology and Genetic Engineering

Human Cloning-The ScienceIn The News

Biotechnology• Use of scientific & engineering principals

to manipulate organisms or their genes

Products of Biotechnology

• Organisms with special biochemical, morphological, and/or growth characteristics

• Organisms that produce useful products

• Information about an organism or tissue that would other wise not be known

Classical Biotechnology• Propagation to get selected characteristics

Plants derived from wild mustard

Techniques for Classical Biotechnology

• Selection

• Hybridization

• Mutation

Hybrid • Offspring from crossing two genetically

similar varieties of a species

• Cross between two different species

Hybrid Vigor• Hybrid improved in certain ways over

parents– Stronger– With higher yields

Important Microbiology Events

• Pasturization – Louis Pasteur (1860s)– Process to kill microorganisms that cause

fermentive change

• Germ theory– Robert Koch (late 1800s)– Germs cause infection– Developed pure culture methods

Antibiotics• Alexander Fleming

(1927)

– Mold that contaminated cultures killed bacteria

– Began process of screening for antibiotics

Molecular Biotechnology• Manipulating genes• Genetic recombination

– Exchange of DNA sequences between molecules

Bacterial Exchange of DNA• Transformation• Transduction • Conjugation

Transformation• Donor bacterium

– Lysed– Releases DNA

• Recipient bacterium– Take up DNA

• Can be induced

Transduction• Virus transfers DNA from donor to recipient

Conjugation

• Donor & recipient make contact

• DNA is transferred

• Transfer in bacteria with plasmids

Plasmids• Extra chromosomal pieces of DNA

• Replicate independently

• Small portion of bacteria’s DNA

• Contain genes that promote transfer

Engineering Gene Transfer• Recombinant DNA technology• Individual genes isolated and transferred

Applications of Biotechnology

• Producing proteins for therapeutic use• Producing vaccines• DNA fingerprinting• Research on genome structure & function• Gene therapy to treat disease• Modification of food

Producing Therapeutic Proteins

• Insert genes into bacteria• Manipulate bacteria to produce proteins• Purify proteins for use

Finding the Gene of Interest• Shotgun cloning

– Isolating & purifying genomic DNA

– Cutting DNA into fragments

– Insert fragments into bacteria or yeast

– Results in complete genomic library

– Library screened to find desired gene

DNA into Gene Fragments• DNA clipped with restriction enzymes

– Recognize certain DNA sequences

Cloning Genes• Restriction fragments into bacteria or

yeast using plasmids or viruses

Complementary DNA (cDNA) Cloning

• Gene of interest is known

• Messenger RNA from gene available

• Use reverse transcriptase to make gene

• Can be expressed in bacterial systems

Gene Synthesis Cloning

• Desired sequence must be known

• Laboratory made gene inserted into yeast or bacteria

• Used for insulin cloning as example

Screening for Desired Genes

DNA Probes• Molecule that binds to a specific gene

• Types of DNA Probe

– Molecules of RNA

– Complementary sequences of DNA

Genetically Engineered Vaccines

• Vaccines stimulate an immune response

• Benefit of genetically engineered vaccine– Non pathogenic

DNA Vaccines

• DNA sequence of pathogen injected • Immune system develops antibodies• Advantages

– No risk of infection– No risk of illness from contamination– Long lasting immune response– Can administer many vaccines in a single shot

DNA Fingerprinting

• DNA fragments amplified

• Fragments drawn through gel

• Bands visualized by dyes

• Humans have unique patterns

Polymerase Chain Reaction(PCR)

• Makes copies of DNA fragments

• Allows for analysis starting with small samples

• Gives large number of copies

PCR can be Automated

Electrophoresis• Separates DNA fragments

DNA Fingerprints & Paternity

Human Genome Project

• Sequence of Human DNA

• 3 billion base pairs

• 30,000 to 40,000 genes

Genomics • Subdiscipline of genetics

• Mapping, sequencing, & analyzing

• Two areas– Structural genomics– Functional genomics

DNA Arrays (DNA Chips)• Allows screening of thousands of genes

Gene Therapy• Uses recombinant DNA to treat

genetic disorders

• Replaces defective genes

• Includes targeted gene repair

Food Modification with Biotechnology

• Increase yield

• Increase quality

• Modification of genes in organisms

• Example: transgenic plants– Genetically altered

Transgenic & Cloned Animals• Dolly

– First cloned animal– Nuclear transfer from cell to produce embryo

Transgenic & Cloned Animals• Bioengineered animals

– Combine desired traits– Cow example:

• Heavy muscle• Low fat

Genetic Engineering Controversy

• Potential dangers exist

• Experiments governed by National Institute of Health

• Genetically modified foods– Common in U.S.– Opposed by Europe

Arguments Against Bioengineering

• Long term safety of engineered foods• Spread of bioengineered genes