DNA samples are "cut" into fragments by restriction enzymes
- the chances of the restriction enzymes cutting the DNA from two different people or species in exactly the same places into exactly the same size fragments is next to impossible
- Therefore, the banding patterns that result from gel electrophoresis are unique to the individual - a genetic fingerprint!
- Identical banding patterns in two different samples mean the sample came from the same individual
- Individuals who have more similarities in the band patterns have more similar DNA = more closely related.
- Evolutionary relationships can also be determined by gel electrophoresis - the more similar the fingerprints, the more closely related the species
- the human insulin gene spliced into bacteria - bacteria make human insulin
Gene Technology
DNA fingerprints
Gel Electrophoresis
http://learn.genetics.utah.edu/content/labs/gel/
What are Transgenic Organisms
Gel electrophoresis separates DNA fragments according to their size.
- DNA samples are cut using restriction enzymes
- small fragments move through the gel faster than large ones.
- the DNA fragments can be seen as bands, each representing a group of same-sized DNA fragments.
DNA Fingerprinting
Organisms with genes from other species in their DNA are called Transgenic Organisms
Fish with jellyfish genes
How?
Uses:
- link suspect to a crime
- confirm familial relationships
- identify the remains of the deceased
- screen for genetic disorders
- determine relatedness between different species
Interpreting a Gel
Genetic Engineering
Human manipulation of Genes
Who's the Father?
Your dog's great great great great great...
... great great grandma
- Humans have been doing this for thousands of years - Selective Breeding of domesticated animals and crops
- Left to chance: Humans bred two individuals showing desirable traits with the hope that their offspring would have those beneficial traits.
- Genetic Engineering removes the element of chance.
Transgenic Organisms
http://learn.genetics.utah.edu/content/science/pharming/
Achieved by removing a gene from one organism and splicing it into the DNA of another.
Creates recombinant DNA - genes with DNA from 2 or more different organisms
bacteria have circular pieces of DNA called plasmids
Cloning
The genetically modified atlantic salmon looks normal, acts normal, and tastes normal; it just grows bigger faster...
Both fish are the same age!
Cloning involves taking the DNA from one organism and using it to create a new genetically identical organism.
Dolly the Sheep - first cloned mammal
GMO Controversy
Pros
- less stress on environment
- Medical/health benefits
- Increased production - more food
Cons
- Safety (?)
- "Superbugs/Superweeds"
- kills non-pests
- Gene transfer
- Ethical - Playing God (?)
Genetically Modified Crops
BT corn - A gene from Bacillus Thurigensis (a bacteria species) that produces a protein toxic to caterpillars is inserted into the corn plant DNA
To Clone or Not to Clone...
In the near future, scientists will have the technology and understanding to clone many different animals, including extinct animals and even humans...
...but should we do this?