DNA Profiling

DNA Profiling

Partial DNA profiles
If any locus is missing an allele, this is considered a partial profile.
Variety of reasons for their occurrence, such as a degraded sample (can occur in site or in storage) or limited quantities of DNA material was collected.
However, partial profiles may still be helpful in determining if an individual could be included or excluded in the investigation

Applying weight to the match
Since any two human genomes differ at about 3 million sites, no two persons (barring identical twins) have the same DNA sequence.

Unique identification with DNA typing is therefore possible provided that enough sites of variation are examined.

To say that two patterns match, without providing any scientifically valid estimate (or, at least, an upper bound) of the frequency with which such matches might occur by chance, is meaningless.

Random Match Probability (RMP)
RMP: is the probability that two randomly selected individuals have identical phenotypes/genotypes by chance alone
With the current panel of genetic markers available to forensic testing, it is not uncommon for the reciprocal of the random match probability determined for a genetic profile to exceed the worlds population several fold.
A random match probability less than 3.9 x 10-11 would convey at least 99% confidence that the evidentiary profile is unique in the population

Random Match Probability is NOT
Chance that someone else is guilty

Chance that someone else left the bloodstain

Chance of defendant not being guilty

[jocelynthomas]

DNA profiling is actually a pretty interesting concept