Lecture 2 - DNA and its applications Flashcards
Mitochondrial DNA
DNA inherited maternally and not unique to every individual
Nuclear DNA
DNA located in the nucleus and unique to every individual
Which type of DNA is unique to every individual?
Nuclear DNA
What is involved in the extraction of DNA
Cells are washed from the sample and the membranes are digested by enzymes. The DNA is purified from cell debris using a binding resin
Quantification of DNA
Measuring both the total and the male DNA in an extract
Amplification of DNA
The regions of interest are targeted and reproduced through utilising a polymerase chain reaction
Analysis of DNA
Capillary electrophoresis to separate the amplification products based on length
What is required for a DNA profile to match the sample?
The same number at all loci and no unexplainable differences
What is required to exclude a DNA profile as a possible match?
One or more unexplainable differences between the DNA profiles
What type of samples contain high cellular content and DNA yield?
Blood, semen and saliva
What types of samples typically contain low amounts of DNA?
Trace DNA left from skin contact with objects
How is a reference DNA sample taken?
Using a Buccal swab taken from the inner cheek and stored on FTA paper
What factors affect DNA profiling
Low yield, poor sample quality (degraded DNA), PCR inhibitors (heme from blood, soil, fabric dyes), DNA mixture and contamination
What determines the numbers given to a DNA profile
The number of tandem repeats (short nucleotide sequences) in specific regions of the DNA
