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Gustatory sensilla in the blowfly Phormia regina contain five phenotypically distinct neurons. The neurons are thought to arise from a common precursor, however, little is known about their lineage or about how each one comes to assume a unique fate. This study examines the possibility that the neurons arise from a repeatedly dividing stem cell, in which case, the neuronal fate may be determined by birth order. To determine if the neurons are born at different times, their times of birth were assessed. This was achieved by using Hydroxyurea to arrest the gustatory neural precursors at different times throughout the development of the sensillum. Thus, each neuron's time of birth, relative to the arrest, was reflected by its presence or absence. The results show that the five neurons are born in a relatively short interval, and hence, cannot arise from five successive divisions of a stem cell. Therefore, the fate of each neuron cannot be determined solely by its time of birth.

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<p dir="ltr"><i>Phormia regina</i> Meigen is a forensically relevant species of blow fly, common in North America and used to estimate the minimum postmortem interval in forensic casework. It is also possible to use blow flies to survey the environment for biotic and abiotic information drawn from both larval and adult stages. There are both forensic and environmental uses for genetic analysis of blow flies. Blow fly kinship is especially useful for detecting postmortem movement of a corpse or to assess abundance of carrion in a given location. To test genetic relationships between individuals, discriminatory loci such as microsatellites, or polymorphic tandemly repeated sequences of DNA are necessary. Here, we characterize novel microsatellites generated from the genome of <i>P. regina</i>. Thirty-four candidate polymorphic loci with conserved flanking regions, have been isolated. To date, seven are heterozygous and polymorphic testing in two lab populations and one wild population. The simple sequence repeats characterized here complement existing loci (N = 6) for greater discrimination for testing relationships between individual flies.</p>

<p dir="ltr">Blow flies are a family of carrion insects that are among the first to arrive in the decomposition process. Blow flies are known to ingest carrion, feces, water, and occasionally nectar to meet nutritional requirements. These behaviors make blow flies a unique organism potentially containing genetic material from a variety of sources within one environment. Their global distribution and ease of capture makes them a strong candidate for resource monitoring and identification. While previous studies have evaluated the suitability of blow flies for vertebrate biodiversity estimates, no work has been done looking at their ability to ingest and store genetic material from plants and microbes present in water. It is also not known how long these DNA signals persist in the gut. Through DNA analysis of the blow fly gut, researchers can identify vertebrates that have recently died in an environment, what plant species are present, and what water source the insect utilized. Through lab colony (Phormia regina) feeding experiments, it was determined that at 25 ˚C and 50 % relative humidity, vertebrate and plant DNA persist in the gut for over 120 hours post-ingestion. Wild sample analysis of flies collected from Yellowstone National Park was performed to identify plant species ingested by P. regina in the wild. Following Sanger sequencing, top hits on BLASTn included Brassicales, Juglans cathyensis, and uncultured Candida. This is the first application of environmental DNA analysis techniques to insects for the purpose of plant identification. This work also attempts to characterize microbial profiles of the gut of P. regina for the purpose of water resource identification. Over a two-month collection period, samples were collected from different water resources across Indianapolis. Flies were exposed to these samples in a controlled feeding experiment, followed by sampling at 0- and 72-hours post-exposure. Gut samples were sequenced using Illumina and Operational Taxonomic Unit clustering grouped reads by sequence similarity for identification. Bacteria classes identified included Gammaproteobacteria, Bacteroidia, Flavobacteria, Alphaproteobacteria, Bacilli, Clostridia, Actinobacteria, Betaproteobacteria, and Fusobacteria. Many bacteria classes were common across water samples, although the abundance of each class changed between samples and across time. These unique microbial profiles can be used to identify water resources for potential contamination and chemical dumping. Further work is necessary to generate microbial profiles from the original water sources themselves and for generation of alpha and beta diversities. Overall, this work spans multiple fields. Species identification is important for biodiversity monitoring and environmental surveys. Utilizing blow fly derived DNA allows for detection of living and deceased vertebrates in an environment, plant life, and water quality within one sample. This work also has implications in forensic science, specifically wildlife forensics and chemical detection of clandestine laboratories and chemical weapon compounds.</p>

Indiana University-Purdue University Indianapolis (IUPUI) / Phormia regina (Meigen), commonly known as the black blow fly is a dipteran that belongs to the family Calliphoridae. Calliphorids play an important role in various research fields including ecology, medical studies, veterinary and forensic sciences. P. regina, a non-model organism, is one of the most common forensically relevant insects in North America and is typically used to assist in estimating postmortem intervals (PMI). To better understand the roles P. regina plays in the numerous research fields, we re-constructed its genome using next generation sequencing technologies. The focus was on generating a reference genome through de novo assembly of high-throughput short read sequences. Following assembly, genetic markers were identified in the form of microsatellites and single nucleotide polymorphisms (SNPs) to aid in future population genetic surveys of P. regina. A total 530 million 100 bp paired-end reads were obtained from five pooled male and female P. regina flies using the Illumina HiSeq2000 sequencing platform. A 524 Mbp draft genome was assembled using both sexes with 11,037 predicted genes. The draft reference genome assembled from this study provides an important resource for investigating the genetic diversity that exists between and among blow fly species; and empowers the understanding of their genetic basis in terms of adaptations, population structure and evolution. The genomic tools will facilitate the analysis of genome-wide studies using modern genomic techniques to boost a refined understanding of the evolutionary processes underlying genomic evolution between blow flies and other insect species.

Indiana University-Purdue University Indianapolis (IUPUI) / The black blow fly, Phormia regina (Diptera: Calliphoridae), is a widely abundant fly autochthonous to North America. Like many other Calliphorids, P. regina plays a key role in several disciplines particularly in estimating post-mortem intervals (PMI). The aim of this work was to better understand the population genetic structure of this important ecological species using microsatellites from populations collected in the U.S. during 2008 and 2013. Additionally, it sought to determine the effect of limited genetic diversity on a quantitative trait throughout immature development; larval length, a measurement used to estimate specimen age. Observed heterozygosity was lower than expected at five of the six loci and ranged from 0.529-0.880 compared to expected heterozygosity that ranged from 0.512-0.980, this is indicative of either inbreeding or the presence of null alleles. Kinship coefficients indicate that individuals within each sample are not strongly related to one another; values for the wild-caught populations ranged from 0.033-0.171 and a high proportion of the genetic variation (30%) can be found among samples within regions. The population structure of this species does not correlate well to geography; populations are different to one another resulting from a lack of gene flow irrespective of geographic distance, thus inferring temporal distance plays a greater role on the genetic variation of P. regina. Among colonized samples, flies lost much of their genetic diversity, ≥67% of alleles per locus were lost, and population samples became increasingly more related; kinship coefficient values increased from 0.036 for the wild-caught individuals to 0.261 among the F10 specimens. Colonized larvae also became shorter in length following repeated inbreeding events, with the longest recorded specimen in F1 18.75 mm in length while the longest larva measured in F11 was 1.5 mm shorter at 17.25 mm. This could have major implications in forensic entomology, as the largest specimen is often assumed to be the oldest on the corpse and is subsequently used to estimate a postmortem interval. The reduction in length ultimately resulted in a greater proportion of individuals of a similar length; the range of data became reduced. Consequently, the major reduction in genetic diversity indicates that the loss in the spread of length distributions of the larvae may have a genetic influence or control. Therefore, this data highlights the importance when undertaking either genetic or development studies, particularly of blow flies such as Phormia regina, that collections of specimens and populations take place not only from more than one geographic location, but more importantly from more than one temporal event.