DNA Flashcards
(13 cards)
what is PCR and what is it used for
polymerisation chain reaction - used as a medical diagnostic tool to detect specific mutations that may cause genetic disease, but in criminal investigations it can be used to identify suspects on a molecular level - DNA profiling
what samples at a crime scene contain biological evidence that DNA can be extracted from
blood, semen, hairs, saliva, bones, pieces of skin
which DNA sequences are used in forensic DNA profiling
non-codinf regions that contain segments of short tandem repeats (STRs)
how are STR alleles detected
the key to DNA profiling is amplification of the copies present using PCR. Primers that are specific to the DNA sequence on either side of the STR are used to cut out the section of DNA we wish to look at
how do we separate the different sizes of DNA sequence
gel electrophoresis with comparison to size standards
what is the difference to our practical when compared to real crime scene applications of PCR
we are only looking at one loci, whereas in real crime scene applications they have to look at multiple loci to improve the power of discrimination
how long did the PCR take
1 hour and a half
what did we add to each of the DNA samples
20ul of MMP - master mix + primers
what did we use to analyse the PCR products
TBE buffer and 3% agarose gels in TBE buffer
what size marker did we use
CSI allelic ladder
what voltage did we run the gel on
10V/cm of gel = 150V for 15cm gels
what did we use to visualise the gels afterwards
gel workstation
what can we workout from the gel workstation
the size of the PCR products, the genotypes of each sample, and if any suspects match the crime scene DNA
