Genetic fingerprinting Flashcards
(7 cards)
What are variable number tandem repeats (VNTRs)?
Some of the genome consists of VNTRs which are the same base sequences repeated many times. VNTRs are non-coding.
Why do different individuals have different numbers of VNTRs?
In non-coding regions we find more differences in DNA between individuals of the same species as mutations in coding regions aren’t usually inherited. Therefore, the probability of two individuals having the same number of VNTRs is very low.
How does genetic fingerprinting work?
1) A sample of DNA is obtained.
2) Restriction endonucleases cut out VNTR regions, PCR can be used to amplify fragments.
3) Incubate with labelled probe (e.g. fluorescent dye, radioactive isotope).
4) Many repeats result in longer fragments. DNA fragments are then placed on agar gel and separated by electrophoresis.
5) Longer fragments travel more slowly than shorter ones, fragment separate which produces a series of bands.
6) Patterns of bands can be compared to another genetic fingerprint to see if we are dealing with the same person.
How are genetic fingerprints used in genetic relationships?
VNTRs are inherited rom parents so they can be used in paternity tests. It can also determine how closely-related 2 people are. The more differences, the more distantly-related.
How are genetic fingerprints used in forensic science?
You can find out if a suspect’s fingerprint matches that from a DNA sample collected at a crime scene.
How are genetic fingerprints used in medical diagnosis?
Inherited genetic disorders: the fingerprint of the faulty DNA region of the parent can be compared to that of an embryo to see if the disorder has been inherited. Tumour diagnosis: fingerprint of DNA of a known type of tumour cell can be compared to that of a cell taken in a tumour biopsy to identify the specific type of tumour.
How are genetic fingerprints used in animal and plant breeding?
Genetic fingerprinting can be used to compare how closely-related 2 individuals of the same species are to avoid inbreeding.
