Abstract
There are criminal cases that no frequently used evidence, for example,
DNAs from the criminal, is available. Such cases usually are
unresolvable. With the advent of DNA metabarcoding, evidences are mined
from environmental DNA and such cases become resolvable. This study
reports how a criminal suspect was determined by environmental plant DNA
metabarcoding technology.
A girl was killed in a rural wet area in China without a witness or
video record. Pants with dried mud was found from one of her boyfriend’s
house. The mud was removed from the pants and 11 more mud or soil
samples surrounding murder scene were collected. DNA was extracted from
the soil. Chloroplast rbcL gene fragments were amplified and
sequenced on a next generation sequencing platform. Of the 2980 ZOTUs in
total from the 12 samples, 1495 ZOTUs were identified to species, genera
or families based on the existing public database. The feast analysis
based on either taxa or taxa plus abundance data demonstrated that the
mud on the suspect’s pants was from the criminal scene. The suspect
finally made a clean breast of his crime. This case implies that plant
DNA in the environment soil is a new source of evidence in determination
of suspects using DNA metabarcoding technology and has high potentials
of extensive applications in criminal cases.
Key words : DNA barcoding; forensics; DNA metabarcoding;
environmental plant DNA