Biotechnology and Genetic Engineering

Human Cloning-The Science In 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