Genetic fingerprinting Flashcards
What is genetic fingerprinting?
The number of times a sequence is repeated at different places in the genome can be compared between individuals
What are VNTR’s also known as?
Short tandem repeats
What are short tandem repeats?
Base sequences that don’t code for a protein and repeat over and over
What is the first step in producing a genetic fingerprint?
PCR is used to produce multiple copies of the DNA fragments
What role do primers play in genetic fingerprinting?
They bind to either side of the repeats and the whole repeat is amplified
What does the amplifying of the repeats produce?
Different length fragments
What is attached to the primer?
Fluorescent tags
What does the DNA mixture that is used in gel electrophoresis contain?
Different lengths of DNA fragments
Where are the different length fragments added into?
The wells on the plate of agarose gel
What is the agarose gel placed in and why?
Buffer solution to conduct electricity
What makes up a control DNA ladder and why is it added to the agarose gel?
Known lengths of DNA fragments
As a comparison to work out the unknown lengths of the sample DNA fragments
What is sent around the agarose gel?
An electrical current
Where is the positive anode on the agarose gel? Why is this the case?
At the opposite side to the wells
So the DNA fragments (negative) move towards the positive charge
Which fragments move the furthest?
The lightest, shortest fragments
Which fragments move the least distance?
The heaviest, longest fragments
How is a genetic fingerprint analysed?
Placed under UV light
Makes the DNA fragments visible
How are genetic fingerprints used in genetic relationships?
- Individuals inherit short tandem repeats from parents
- If two fingerprints are a close match, then they are closely related
- Used in paternity tests
How are genetic fingerprints used to look at genetic variability within a population?
- The greater the number of bands that don’t match between two fingerprints, the more genetically different individuals are
- The more the number of repeats varies at several places, the greater the genetic variability within a population
How are genetic fingerprints used in forensic science?
- Used to compare DNA samples from the crime scene with the DNA of any suspects
- The DNA is obtained from each sample and replicated using PCR
- Gel electrophoresis then used
How are genetic fingerprints used in medical diagnosis?
- A genetic fingerprint, in medical diagnosis, can refer to a unique pattern of several alleles
- You can diagnose genetic disorders and cancer
- Identifies a broader, altered genetic pattern
How are genetic fingerprints used in animal and plant breeding?
- Used to prevent inbreeding which decreases the gene pool
- Inbreeding also leads to a higher risk of genetic disorder and produces health, productivity and reproductive problems
- Identify the least related individuals
