How do we use PCR and gel electrophoresis to determine a per

How do we use PCR and gel electrophoresis to determine a person\'s STR genotype?

Solution

Answer=

use of PCR to determine a persons STR genotype

STR loci are polymorphic regions found in the genome that are used as genetic markers for human identity testing

steps = consists of 3 steps

1] Denaturation = the sample is heated upto 94-95^oC for 30 sec.

this separates double stranded DNA allows primer access

2] Annealing= sample is kept at 55-65^oC allows formation of hydrogen bonds between primer & complementary DNA

3] Extension= sample is heated to 72 ^oC

each cycle takes 5 min.

repeat these cycles

1] Genomic DNA extraction=

2] PCR primer & amplification

3] STR analysis & electrophoresis

Use of electrophoresis to determine persons STR genotype =

Electrophoresis gel genotyping is the process of experiments that complements nucleic acids for genetic analysis

DNA & RNA anaysed for size

STR are regions of genome composed of approximately up 1-5 bases & repeated upto 17 times

they may be simple ,compound or complex

only a selected number of STR markers are used in forensic DNA profilling

DNA are separated on the basis of size

a porous gel matrix is used

gel is floating in buffer solution to insure PH level is maintained & applied electric current is conducted

samples to be analysed to be placed in small wells at the top of gel

A control sample & standard will run simultaneously as current is applied

negatively charged DNA will migrate towards positively charged anode

on basis of their size