Identification from bite marks in a sexual assault case involving multiple assailants by DNA profiling

Abstract

Bite mark evidence is often introduced as being close
to DNA in terms of accuracy. Bite marks are generally
found at the scene of violent crime murders, sexual
assaults and are an extremely difficult process to
collect the bite marks/saliva sample very lightly,
otherwise, only victim profile will be generated. On
examination of victim's right breast, a patterned
injury was discovered and determined to be from
adult male’s teeth. Evidence was collected by the
forensic doctor according to established techniques
including recovery of saliva from the bite mark area
despite the body. DNA analysis by PCR using
polymorphic STR markers revealed a DNA profile of
mixed origin. With the advent of more sensitive
typing methodologies, fingernails clipping for foreign
DNA, as well as swabs collected from the area on the
victim's body (kissed, licked, genital area, bitten area
from breast and lips), are analyzed. In addition, finger
swabs for nail scrapping in the case of digital
penetration could also be collected from the suspect
for DNA analysis, findings new repeats of DNA.
Generally, Victim’s DNA profile, a genotype
contribution from the perpetrator was identified as a
minor component. Thus the DNA typing results from
the bite mark correlated with the DNA typing results
obtained from other biological trace evidence
identified from the victim's genital samples. The bite
mark and the DNA evidence were used to screen
suspects and played an important role in obtaining
resolution of this case. In this study DNA profiled
from the breast swab from bitten area, finger swabs,
and a control sample of assailants were obtained for
all STR loci using AmpflSTR Identifier kit.