Download - 13 genetic engineering bw
Genetic Engineering
- Archeological evidence shows that humans began cultivating plants and animals for food about 10,000 years ago
- Specific organisms were bred to improve future generations
- Simple form of applied genetics
CONTROLLED BREEDING
Manipulates the characteristics of the off spring by selecting parents
with specific phenotypic traits
Types of Controlled Breeding
1. Selective BreedingProcess of choosing a few individuals to serve
as parents for next generation
- Luther Burbank: Californian plant breeder (early 1900s)
- responsible for 800 new plant varietiesEx: seedless grape
Spineless cactusBurbank potatoDaisies
- Corn: bred for 7000 years- Small horses, dogs, cats: bred for different
breeds
Types of Controlled Breeding
2. Inbreeding
Process of crossing individuals with similar characteristics so those characteristics appear in offspring
- purpose: to maintain or intensify desireable traits
- individuals closely related (same species)
- more risk of passing recessive genetic defects
ex: poodles: joint deformities maine coon cats: heart murmurs
Types of Controlled Breeding3. Hybridization
Process of crossing individuals of different but related species
- produces hybrids
- hybrid vigor: offspring are hardier than parents
(grow faster, larger, and are healthier)
Ex: cattle - disease resistant corn – yield 10 times more than old
varieties
broccoflower liger zonkey leopon tangelo
Types of Controlled Breeding4. Induced Mutations (1927)
Polyploidy: common in plants, deadly in animals
- plants treated with chemicals to prevents cell plates
- resulting cells have multiple sets of chromosomes
- results in larger fruit and vegetables
• Techniques were forerunners modern genetic engineering
• Today geneticists engineer changes directly into an organismsDNA
GENETIC ENGINEERING (GENE SPLICING/GENE
CLONING)
• Process of direct gene manipulation
• Goal: to introduce new characteristics into organisms to increase its usefulness
• Basic steps of genetic engineering involve:1. isolation of gene2. manipulation of gene/cloning gene -PCR3. reintroduction of DNA into model organisms
animation: steps in cloning a gene
Genetic Engineering TechniquesI. Making Recombinant DNA
1. Restriction enzymes cut DNA into fragments that can be isolated and separated
- very specific proteins, recognizes and cuts DNA at specific sequence into pieces
Ex: EcoRI – cuts DNA whenever C-T-T-A-A-G sequence occurs
2. Production of recombinant DNA
- DNA composed of fragments of DNA segments from at least two different organisms
- restriction enzymes cut bacterial plasmids (extra circular DNA molecules in bacteria)
- plasmids have “sticky ends” (unpaired bases)
- original DNA is attached to plasmid sticky ends
Genetic Engineering Techniques
3. reintroduction of DNA into bacterial vector
- recombinant DNA taken up with bacterial
DNA and now produced by bacterial cell
- recombinant DNA is isolated and CLONED
- PCR (polymerase chain reaction) induced
- purpose: to make 1000s of recombinant plasmids
PCR animation
4.DNA sequencing
- Process of reading exact order of bases in fragment of DNA
- makes it possible for scientists to make sure gene of interest has been cloned
rDNA: animation
Genetic Engineering Techniques
II. Microinjection - Process of injecting genetic material containing the new gene into the recipient cell
- direct gene transfer, no use of vectors
- in large cells done with fine tipped glass needle
- somehow injected genes find the host cell genes and incorporate themselves among them
Ex: most common method of making genetically altered mice
Genetic Engineering Techniques
III. Bioballistics
- projectile methods that use metal slivers to deliver the genetic material to the interior of the cell.
- small slivers coated with genetic material
- once in the cell, genetic material is transported to nucleus where it is incorporated among the host genes
IV. Electro and Chemical Poration
- process that creates pores or holes in the cell membrane to allow direct entry of new genes
- done by bathing cells in solutions of special chemicals or weak electric current
TRANSGENIC ORGANISMS /GENETICALLY MODIFIED
ORGANISMS (GMO’s)
• organisms that contain foreign genes
TransgenesisThe use of recombinant DNA techniques to introduce new characters (ie. genes) into organisms (including humans) that were not present previously.
Types GMO’sI. Bacteria
-human DNA inserted in bacterial plasmid
-recombinant produces large volumes of proteins
Ex: human growth hormone (HGH), insulin
Types GMO’sII. Plants
- 1986: Howell - inserted gene to producer enzyme luciferase (fireflies)into tobacco plant
- enzyme in fireflies
- only produces enzyme in conditions without light
(gene expression)
- cloned cells reproduced tobacco plant that
glowed in the dark
Making Transgenic Crops
Steps
1. extracting DNA
2. cloning a gene of interest
3. designing the gene for plant infiltration
4. transformation
5. plant breeding
Other Transgenic PlantsBT corn (bacillus thuringiensis)
Soil bacterium that resists insecticidal toxins: makes corn resistant to pests and less need for pesticides
Other Transgenic Plants
Calgene tomato “Flavr Savr”
stays fresh longer because enzyme to break down pectin are reduced by genetic alteration
Types GMO’sIII. Animals
Transgenic sheep:
human gene for milk production inserted into sheep and now produces proteins of human milk
Oncomice (cancer mice)
Used in medical research to find cures for cancer
Other examples of transgenic animals:
Transgenic chickens: - grow faster and larger in close quarters - produce more protein in their egg whites- produce human protein drugs in their eggs
Transgenic pigs: - produced by fertilizing normal eggs with sperm cells that have incorporated foreign DNA
- may someday be able to produce transgenic pigs that can serve as a source of transplanted
organs for humans
video
Cloning Animals 1997 Wilmut (Scottish)
- cloned sheep “Dolly”
- process: nucleus of egg is replaced with nucleus of adult , resultant organism identical to adult
- now companies are making
cloning available to pet owners for
their beloved pets who die
- is this ethical?
Genetic Savings and Clone
Ethics of GMOs and Cloning
• Imagine cloning humans to make armies.
• Could clones and GMOs be patented?
• Are genetically modified livestock and agriculture harmful?
• Would only perfect genetically engineered infants be desirable.
APPLICATIONS OF G.E. The first genetic fingerprint 1984
Electrophoresis Animation Detail
1. DNA Fingerprinting (used in forensics)
Process of identifying and distinguishing DNA of individuals
- each person has unique repeat sequences and numbers of
non coding introns
- sample is taken and DNA is extracted
- fragments of repeats of introns are labeled and put into a gel electrophoresis where they separate
- create banding patterns which are unique for every human
APPLICATIONS OF G.E.- Once banding patterns are apparent they are transferred
to a Southern Blot for identification
Southern blot animation
Applications of Genetic EngineeringDNA Fingerprinting
Applications of Genetic EngineeringDNA Fingerprinting
Restriction fragment length polymorphisms
Applications of Genetic EngineeringDNA Fingerprinting
APPLICATIONS OF G.E.Microarray
APPLICATIONS OF G.E.2. Gene therapy
Creating transgenic humans to erase genetic diseases
- recombinant DNA put directly into human cells or through virus vectors
APPLICATIONS OF G.E. 3. Pollution control
- genetically altered bacteria used to decompose garbage
sewage, and petroleum products
Unlike the left tower, which uses chemicals, the tower on the right at this wastewater-treatment plant now uses bacteria-covered foam blocks (inset) to eliminate the hydrogen sulfide bubbling from treated sewage.
Deshusses/PNAS
APPLICATIONS OF G.E.
4. Medicines and Vaccines produced by bacteria and viruses
- E coli: used to make human insulin
- hamster cell cultures: used to make TPA (tissue plasminogen activator)- dissolves blood clots in heart attacks
- EPO (erythropoiten): increases red blood cell production
- interferon: fights viral infections, increases immunity
- vaccines
vaccine animation
APPLICATIONS OF G.E.
5. Agriculture and livestock
- hardier, disease and environmentally resistant fruits and vegetables
- larger sturdier animals
HUMAN GENOME PROJECT
• begun in 1990: coordinated by US Dept of Energy and NIH
• purpose: - to identify the 20-25,000 genes in human DNA
- to determine sequences of 3 billion DNA base pairs
- to license info to biotech companies to foster new medical applications
• international: US, England, China, France, Germany, Japan
• used combined genomes of anonymous small number of people
Study for the test !