Molecular Identification of Forensically Significant Coffin Flies (Diptera: Phoridae) from Eastern India Using COI Barcodes

Abstract

Coffin flies (Diptera: Phoridae) are crucial to forensic studies because they can inhabit coffins or be found on buried corpses, thus aiding in determining the postmortem interval (PMI) and body relocation in criminal cases. But phorid flies are hard to identify because they are small, have cryptic appearances, and lack the proper taxonomic expertise to quickly identify both adult and larval forms. Thus, entomologists tend to concentrate increasingly on alternative methods to expedite the identification process and circumvent this problem. A short mitochondrial cytochrome oxidase I (COI) gene fragment is a potent marker for accurate molecular identification and robust phylogenetic analysis. Three phorid fly species, belonging to the genera Megaselia and Puliciphora, were collected in the current study to evaluate the effectiveness of the COI gene in identifying them. Seven sequences representing three species were generated and uploaded to GenBank and BOLD. COI barcodes successfully differentiated between species, with Kimura-2-Parameter (K2P) intraspecific and interspecific genetic divergences ranging from 0% to 1% and 14.5% to 34.1%, respectively. NJ (Neighbour-Joining), ML (Maximum-Likelihood), and BA (Bayesian Analysis) methods demonstrated strong reciprocal monophyly and accurate species differentiation. This study provides the first COI barcodes of M. rufipes and P. borinquenensis from India.  The present study demonstrates the reliability of COI barcoding as a molecular method for identifying phorid species. Forensic entomological evidence would be improved by the inclusion of regional COI sequences in reference libraries, such as GenBank and BOLD, thus serving as essential forensic markers for criminal investigations and wildlife poaching cases.