Comparitive genetics of two selective lines of the secondary screwworm, Cochliomyia macellaria (Diptera: Calliphoridae)

The forensically important blowfly Cochliomyia macellaria (Diptera, Calliphoridae) is widely distributed across the United States and is a primary coloniser of carrion utilised by forensic entomologists in the estimation of postmortem interval (PMI). In order to estimate an accurate PMI, forensic entomologists rely upon already published species-specific developmental data in addition to location temperature and specimen size. However, these estimations can be variable due to climatic differences from one geographical region to another and also from genetic variation between or within fly populations. In order to reduce this variability, we have selected for development time across three separate populations of C. macellaria collected from central Texas, between a fast and slow genotype. With genomic DNA data acquired from 50 individuals from each location in the base population (F₀) and additionally at both development rates in a latter generation (F₂₆) using Illumina Hi-Seq technology, we identify molecular markers for each genotype illustrating the variation between these selection lines and the effects of these polymorphisms on development rate of C. macellaria. Consequently, this observed variation can assist forensic entomologists in the quest to generate a more accurate PMI estimation.