Understanding Blow Fly Genetic Variation May Reduce Error Rates in Time of Death Estimates

• NCJ Number: 250410
• Date Published: November 2016
• Length: 2 pages
• Grant Number(s): 2012-DN-BX-K024
• Agencies: NIJ
• Publication Type: Research (Applied/Empirical); Program/Project Description
• Award: Genomic tools to reduce error in PMI estimates derived from entomological evidence

Annotation

The goals of this research project were to obtain quantitative and functional genetic information for the blow fly commonly used as a forensic indicator, Cochliomyia macellaria Fabricius, with the expectation that the resulting information could be used to develop both short-term and long-term strategies for using genetic tools to account for uncertainty in forensic estimates of blow fly age.

Abstract

This research aimed to reduce the gap in information regarding the impact of genetics in forensic entomology, which is important because t forensic entomologists rely on estimates of the age of blow flies on a corpse to determine time of death. Understanding the consequences of genetic variation is an important step in reducing error rates. The research shows that natural genetic variation has the potential to drive average development-time differences of up to 6 days at 25 degrees Celsius (77 degrees Fahrenheit). Although the time difference occurred in a controlled experiment rather than a natural environment over time, it does indicate that genetic variation influences blow fly development time. Temperature is also likely to have a role in development time. The project is currently investigating the nature of thermal plasticity in the selected lines of blow flies. Results from the selection experiment indicate that there is potential for thermal interactions with development-time genotypes and that these are likely to influence other traits, including size, which is forensically informative.