3.5 Genetic Modification Flashcards
PCR
Polymerase chain reaction
Copies and amplifies minute quantities of DNA
PCR is a way of producing…
Large quantities of a specifc target sequence
PCR is useful when
There is only a small sample of DNA available
Crime scene samples of blood, semen, hair
3 Steps of PCR
Denaturing
Annealing
Elongation
Denaturing
DNA sample is heated to separate it into 2 strands
Annealing
DNA primers attach to opposite ends of the target sequence
Elongation
A heat tolerant DNA copies the strand
Gel electrophoresis
Separate DNA fragments according to size (move in electrical field)
Steps of gel electrophoresis
-Sample of DNA is placed in block of gel
- Electric current is applied
-Smaller samples move faster to the bottom through gel
Why does the DNA move towards the bottom (anode)
DNA is negatively charged. So moves to positive anode
Use of gel electrophoresis
DNA profiling
STR
Short Tandem Repeats. In non-coding regions. What makes individuals unique
How are profiles collected to be compared
STR are cut with restriction endonucleases. Form fragments
Process of DNA profiling
The steps starting from collectig the DNA
Collected and amplified usinh PCR
Cut with restriction enzymes to generate fragments
Fragments are separated in gel
DNA is then analyzed
2 applications of DNA PROFILING
Paternity Tests
Foresic investigations
Human Genome Project
International project established to sequence the 3 billion base pairs (25,000 genes) in the human genome
Outcomes of the HGP
Mapping
Screening
Medicine
Ancestry
Mapping
Know the number, location, and base sequence of
Screening
Detect sufferers carriers of genetic disease conditions
Medicine
Develop improved treatments
Ancestry
Improved insight on the origins, evolution, and historical migratory patterns of humqns
The same sequence of polypeptide means
Genetic code is universal
Gene transfer steps
DNA Extraction
Digestion and Ligation
Transfection and Expression
DNA Extraction
Plasmid is removed from bacterial cell
Gene of interest is removed from organisms genome using restriction enzymes
Both are amplified using PCR
Plasmids
Small circular DNA molecules
Digestion and Ligation
Plasmid is cut with same restriction enzyme
Cutting allows for the 2 DNA’s to fit together
Gene of interest and plasmid are spliced together by DNA ligase
Recombinant plasmid
When DNA ligase splices plasmid and gene together
Transfection and Expression
The recombinant plasmid is inserted into the desired host cell
The cell will hopefully express the desired trait
2 examples of GMO crops
Tomatoes. Delying the natural process of softening the fruit
Maize crops. Toxic plants protected from insects
2 examples of GMO animals
Sheep to produce more wool
Sheep to produce milk used to treat individuals suffering from hereditary emphysema
Benefits of GMO
Less use of chemical pesticides
Makes crops grow in other regions (reduces deforestation)
Increased productivity of food production
Harm of GMO
Accidental release of GMO organisms into environment mught compete with native species
Reduces genetic variability
Clone
Group of identically identical organisms or cells from single parent
SCNT
Somatic Cell Nuclear Tranfer
Method of reproductive cloning using differentiated animal cells
Steps of SCNT
1) Female animal is stimulated with FSH to produce eggs
2) Nucleus is removed
3) Egg is fused with nucleus from somatic cell of another sheep
4) Electric shock stimulates egg to divide
5) Now you have a clone
Value for cloning
Can cure serious diseases with cell therapy
Stem cells can used from undeveloped embryos (abortions)
Cells are taken from when embryo feels no pain
Against cloning
Creation and destruction of human embryo
Embryonic cells can cause tumors
Costly
