Abai, MR

6th International Congress of DipterologyDNA-based identification of Forensically Important DipteraWells, J.D.Department of Biology, West Virginia University, Morgantown, WV 26506, USAIt has become relatively easy and inexpensive to generate a moleculargenotype for many of the insect species used as forensic evidence. Itseems likely that DNA-based methods can be used to identify a specimen,thus overcoming the current lack of diagnostic characters for manyimmature forms. For this advance to occur, greater attention should bepaid to the logic of experimental design and method validation. In manyways the situation is analogous to constructing a morphological key. Thereference database must include a taxon sample that is useful for a realdeath investigation, the reference specimens must be properly identified,and replication must be sufficient to estimate intraspecific variation andpopulation genetic structure. The popular GenBank/EMBL/DDBJsequence database, although extremely convenient, is well known tocontain many erroneous records. Therefore careful consideration shouldbe given to judging the reliability of a published genotype. Often apolymorphic locus that is a candidate for distinguishing closely relatedspecies is not monophyletic. Validation of a cytochrome oxidase I (COI)data set for identifying forensically relevant Chrysomyinae (Calliphoridae)in North America was successful, with hundreds of specimens supportingconcordance between morphologically defined species and haplotypelineage. In contrast a global sample of Luciliinae (Calliphoridae)uncovered widespread COI paraphyly, and our conclusions based onearlier smaller samples were in error. In summary, many loci andgenotyping methods are potentially useful for DNA-based identification ofcarrion insects, but the utility of a given method cannot be known prior toempirical validation. The binomial confidence interval is proposed as away to estimate a useful sample size.Key Words: DNA, Calliphoridae, molecular systematics, forensic297