Gene Technology- Genetic Fingerprinting Flashcards
What are variable number tandem repeats (VNTRs)?
Base sequences that don’t code for proteins and repeat next to each other over and over
What is genetic fingerprinting?
Genome is compared between individuals
Why is the probability of two individuals having the same genetic fingerprint very low?
Because the chance of two individuals having the same number of VNTRs at each place they’re found in DNA is very low
How is a genetic fingerprint made?
- A sample of DNA is obtained
- PCR is used to make many copies of the areas of DNA that contain the VNTRs
- You end up with DNA fragments where the length corresponds to the number of repeats the person has at each specific position
- A fluorescent tag is added to all the DNA fragments so they can be used under UV light
- DNA fragments undergo electrophoresis
- DNA fragments are viewed as bands under UV light
What happens during electrophoresis?
- DNA mixture is placed into a well in a slab of gel and covered in a buffer solution that conducts electricity
- An electrical current is passed through the gel- DNA fragments are negatively charged so they move towards the positive electrode at the far end of the gel
- Small DNA fragments move faster and travel further through the gel, so the DNA fragments separate according to size
What are the uses of genetic fingerprinting?
Determining genetic relationships and determining genetic variability within a population
How can genetic fingerprinting be used in forensic science?
- DNA is isolated from all the collected samples
- Each sample is replicated using PCR
- PCR products are run on an electrophoresis gel and the genetic fingerprints produced are compared to see if any match
- If the samples match, it links a person to the crime scene
How can genetic fingerprinting be used in animal and plant breeding?
To prevent inbreeding, which decreases the gene pool
