genetic fingerprinting Flashcards
(4 cards)
1
Q
what are variable number tandem repeats?
A
base sequences that don’t code for proteins and repeat next to each other. The length varies from person to person
2
Q
what is genetic fingerprinting
A
comparing the number of times a sequence is repeated at different places in individuals
3
Q
obtaining a sample for electrophoresis
A
- sample of DNA is obtained
- PCR mask many copies that contain VNTRs and primers are used that bind to either sides of these repeats and so whole repeat is amplified
- results in DNA frags where length corresponds to number of repeats at each specific position
- fluorescent tag is added to frags so they can be viewed under UV
- they undergo electrophoresis
4
Q
electrophoresis
A
- DNA mixture is placed in a well in a slab of gel and covered in a buffer solution that conducts electricity
- electrical current passes through gel
- DNA frags are negatively charged so mover towards positive electrode at far end of cell
- small DNA fragments move faster and further so frags separate according to size.
- viewed as bands under UV light - this is the genetic fingerprint
- fingerprints are compared, if both have a band at the same location is means they have the same number of nucleotides so same number of VNTRs
