GENETIC FINGERPRINTING

Question 1

VNTRs ( variable number tandem repeats)

Answer 1

• base sequence that donot code for proteins and repeat next to each other over and over
• 95% of human dna is made up of introns which contains VNTRs.

Question 2

genetic finger printing

Answer 2

genetic fingerprinting is a technique that can detect differences in peoples dna.
- it uses VNTRs
- probability of two individuals having identical VNTRs is extremely low so vntrs analysis is used.

Question 3

probability of same genetic finger printing

Answer 3

• probability of same genetic finger printing is ver low because the probability of two individuals having same number of vntrs at each place is very low.

Question 4

process involved in genetic fingerprinting

Answer 4

1. collection and extraction of dna
2. digestion using enzyme and amplification using pcr
3. separation using gel electrophoresis
4. hybridisation ( dna probe)
5. development
6. analysis

Question 5

electrophoresis

Answer 5

• dna samples are loaded in small wells in agar gell. the agar gell is then placed in a buffer liquid with electric voltage applied
• dna is negatively charged so dna sample moves through gel towards positive end.
• agar gell creates resistance for moving dna so smaller pieces of dna can move further
• different length of dna vntrs are separated
• alkaline is then added to separate double strand of dna.

Question 6

mechanism process of genetic finger printing

Answer 6

1. dna sample is collected from blood, hair follicles or saliva
2. pcr is then used to amplify the amount of dna
3. restriction endonuclease are added to cut dna into fragments
   4..dna samples are loaded in small wells in agar plates and gel electrophoresis takes place.
   5, dna probes which are then radioactively or fluorescently marked are added into the agar plate . radioactive probes attatch to specific fragments
4. dna fragments are transferred from the agar gell in a nylon membrane because the gel cracks as it dries.
5. nylon sheet is then exposed to x ray light if radioactive gene probes were used or under uv light if fluorescent gene probes were used.
6. two genetic fingerprints can then be compared. if both finger prints have a band at the same location on the gel it means they have same number of nucleotides and same number of VNTRs - its a match. yippie