Biology Reference
In-Depth Information
murders, the addition of samples from high volume crime such as burglary resulted
in an increase in DNA profiles on the NDNAD; the majority of matches are to
high volume crime but there are invariably matches to more serious crimes such as
murder, rape and assaults (Figure 10.3) [8, 9].
In the UK, approximately 1 in 20 people are on the NDNAD; given that over 80%
of all samples on the NDNAD come from males and that there are approximately
30 million males in the total population, this equates to over 12% of the total male
population [4, 8]. With such a large number of DNA profiles held on the NDNAD
there is currently a 58% chance that a DNA profile obtained from an incident will
match a DNA profile on the NDNAD.
Familial searching
Familial searching is based on the principle that family members share more of their
DNA than more distantly related individuals and therefore searching a database using
a close family member may enable the identification of a suspect [10 - 13]. It has
been implemented by the Forensic Science Service of the UK and is used when there
is not a full DNA profile match between the crime scene and the NDNAD samples,
but a match is achieved at 15 or more alleles and the perpetrator most likely lived in
the vicinity of the incident. While the person on the NDNAD cannot be the donor of
the sample obtained from the crime scene, it is highly likely that the originator of the
sample is a relative of the person with a partial match [11]. Familial searching is an
effective intelligence tool; however, there are judicial and ethical issues concerning
its use [14].
Familial searching
Craig Harman was the first person to be convicted of an offence following a link
between a sample taken from a scene and a relative of the perpetrator. In March
2003, Craig Harman, then 19, was walking over a footbridge spanning the M3
motorway to the west of London when he dropped a brick on passing traffic.
The brick struck and broke the windscreen of a lorry, causing a fatal injury to
the driver. The brick was examined for the presence of biological material, and
fingerprints and a DNA profile obtained. The DNA profile did not match in full
with any person on the NDNAD but 16 of the 20 alleles matched a genetic
relative of Craig Harman. A separate complete match was obtained between
the samples obtained from the brick sample taken from Craig Harman after he
was linked to the crime through the partial match. Craig Harman pleaded guilty
to manslaughter.
