Forensic Science Flashcards
what are the applications of DNA profiling in forensics
criminal cases (matching suspects with evidence).
convicted offender DNA databases
mass disasters (DVI) for ID
missing persons investigations
parentage testing (if there is a criminal element)
Historical investigations
Describe the stages and methods of DNA profiling
- DNA extraction: manual and automatic, there is often complex inhibitors and substrates.
- DNA quantification: RT PCR
- PCR amplification: Multiplex PCR via thermacyclers
- DNA amplification: via capillary electrophoresis.
what are two kinds of DNA polymorphism that can be used to distinguish people, what is used in forensic DNA profiling.
SNP and STR,
STR or short tandem repeats are used in forensics.
What are the desirable features of STR in terms of forensics.
High heterozygosity (can differentiate people)
Regular repeated units (predictable alleles).
distinguishable alleles.
robust amplification
can be multiplexed (requires less DNA from a sample.
they produce smaller products (which is good for degraded DNA).
what system is used for Multiplex at pathwest
powerplex 21 which shows fragment sizes and also uses fluorescent dyes.
DNA profiles can
absolutely exclude
DNA profiles cannot
absolutely include.
the chances of two people having the same DNA profile are less than 1 in
a billion
what can be determined from a DNA profile
gender
what cannot be determined from a DNA profile
ethnicity, skin colour appearance.
what is the WA state database
WA DNA database
what is the Australian national database
NCIDD National criminal investigation DNA database
what is the proposed future of DNA profiling
Rapid DNA instruments
Next generation sequencing (NGS)
Massively parallel sequencing. (MPS)
