NCJ Number
205146
Journal
Journal of Forensic Sciences Volume: 49 Issue: 2 Dated: March 2004 Pages: 341-344
Date Published
March 2004
Length
4 pages
Annotation
This study analyzed various methods of storing maggot crop in order to discover how to best preserve DNA for later analysis.
Abstract
Insects and other arthropods contain valuable forensic evidence concerning the postmortem interval (PMI) of victims. As such, entomological evidence is often collected and preserved for later analysis. The method of preservation becomes important if later DNA analysis of the maggot crop content is attempted. The current preservation methods widely in use may not be the best methods for preserving DNA evidence. In the current study, maggots fed on human tissue were preserved under eight conditions: no fluid at -70 degrees C, no fluid at 4 degrees C, no fluid at 24 degrees C, 70 percent ethanol at 4 degrees C, 70 percent ethanol at 24 degrees C, 95 percent ethanol at 24 degrees C, Kahle’s solution at 24 degrees C, and formaldehyde at 24 degrees C. Maggots were dissected at 2 weeks, 8 weeks, and 6 months of preservation. Human DNA was quantitated from maggot crop extractions and amplification of the mitochondrial DNA (mtDNA) and short tandem repeat (STR) loci was attempted. STR’s and mtDNA were successfully amplified from maggots stored in ethanol or without any fluid. The best results were achieved with maggots stored without any preservation fluid at -70 degrees C. The recovery of DNA was reduced in maggots stored in formalin-containing preservation solutions, indicating that over time these solutions may permit the degradation of DNA inside the maggot crop. The findings indicate that freezing maggots at a temperature below refrigeration is the best method of preserving DNA. If freezing is not possible, maggots should be stored in a solution of ethanol. Tables, references