Gene expression and development in blowflies: A method to more precisely estimate postmortem intervals
The use of insects in forensic entomology has become one of the most helpful tools for estimating post mortem interval (PMI). Within minutes of death, Calliphoridae flies colonize human corpses and are the most accurate to estimate PMI. Currently, length measurements of larvae combined with environmental temperature, as well as the number of posterior spiracles present are used to estimate the developmental stage of maggots. There are many drawbacks to using these methods for PMI determination, including shrinkage of larvae as the third instar ends and variation among growth rates. Therefore, alternative methods are needed to increase the precision of PMI estimation. Molecular studies, especially those including Drosophila melanogaster, have helped scientists understand gene expression and regulation. Throughout the life cycle of a fly, thousands of genes are up- and down-regulated, thus if one could determine the level at which a gene is expressed it may provide an estimation of age. The third instar is the longest and most difficult stage in Lucilia sericata to age, therefore ideal for gene expression analysis. Six genes were examined in the insect including ADP/ATP translocase, cuticle 1, chitin synthase, chymotrypsinogen, alpha trypsin, and aminopeptidase. Based on the research presented here, they show unique patterns that can be used to estimate larval development.
0339: Forensic anthropology