Biology Reference
In-Depth Information
Posterior Odds:
in terms of a court case these are the odds of guilt of a defendant
after the presentation of all evidence. It is the posterior odds that the judge or jury
consider when coming to a verdict.
Primer:
oligonuclceotide that binds to complementary single-stranded DNA and acts
as a priming site for the initiation for the synthesis of the complementary strand by
DNA polymerase.
Prior Odds:
in terms of a court case these are the odds of guilt of a defendant
before the presentation of forensic evidence and may be considered as based on the
non-scientific evidence.
Purine:
nitrogenous bases found in nucleic acids. The purine bases are adenine and
guanine.
Pyrimidine:
nitrogenous bases found in nucleic acids. The pyrimidine bases are
cytosine and thymine.
Restriction Enzyme:
enzyme with endonucleic activity that cuts DNA at specific
sequences. An example is
Eco
RI that cuts within the sequence GAATTC.
Restriction Fragment Length Polymorphism:
the detection of length or sequence
variation after cleaving DNA with a restriction enzyme (see above), separating on
a gel, transferring to a membrane by Southern blotting (see below) and detection
using a small section of DNA within the sequence between two restriction sites.
RFLP testing was used in the detection of minisatellites.
Short Tandem Repeat (STR):
polymorphic region of DNA where alleles differ in
the number of tandemly arranged core repeats. STR alleles typically range in size
between 100 bp and 400 bp. Also known as microsatellites.
Single Nucleotide Polymorphism (SNP):
the occurrence of two (or more) alleles at
a single base position within the genome. SNPs are typically biallelic: transitions
(see below) are more common than transversions (see next page). To be considered
as a population level SNP polymorphism the rare allele should be at a frequency
greater than 1%.
Southern Blot:
a technique that is used to transfer DNA from a gel onto a nylon
membrane.
Te l omer e :
the terminal regions at the tips of the chromosomes. Satellite DNA forms
much of the telomeric regions.
Theta (
) Statistic:
a measurement of inbreeding within a population. Theta is often
used interchangeably with F
ST
in forensic genetics.
Transition:
the change in a base from a purine (see above) to a purine (A/G) or a
pyrimidine to a pyrimidine (C/T).
θ
