This study tested the hypotheses that foraging insects can acquire human DNA from the environment and that insect-delivered human DNA is of sufficient quantity and quality to permit standard forensic analyses.
Houseflies, German cockroaches, and camel crickets were exposed to dusty surfaces and then assayed for human mitochondrial and nuclear loci by conventional and qPCR, and multiplex STR amplification. Over two experiments, 100 percent of insect groups and 94 percent of dust controls tested positive for human DNA. Of 177 individuals, 33-67 percent tested positive and 13 yielded quantifiable human DNA (mean equals 0.022 +/- 0.006 ng; mean dust control equals 2.448 +/- 0.960 ng); 4 had at least 1 positive allele call for 1 or more locus; 8 others showed multiple peaks at some loci. Results imply that application to routine forensic casework is limited given current detection methodology yet demonstrate the potential use of insects as environmental samplers for human DNA. (Published Abstract)