Assessment of post-mortem submersion interval using total aquatic decomposition scores of drowned human cadavers.

Investigating drowning-related deaths remains a significant problem for forensic personnel all over the world. The previously published decomposition scoring method like the total aquatic decomposition (TAD) score promises to estimate the correct post-mortem submersion interval (PMSI) in aquatic habitats through the assessment and calculation of the decomposition rate and accumulated degree days (ADD). The current study comprised of 53 drowned death cases belonging to various districts of Haryana from May 2016 to August 2017. The regression and Pearson's correlation indicated a significant correlation between the TAD scores and the actual ADD (calculated through water temperatures) (r2  = 0.917) and between the actual and the estimated ADDs (calculated through TAD scores used by Heaton et al. [21]) (r = 0.9585). The results indicated that the estimated ADD tends to over predict the PMSI compared to the actual ADD. It is further confirmed by paired t-test, which showed the mean of actual ADD (mean = 349) to be significantly lower than the mean of estimated ADD (mean = 663). Moreover, these methods will help forensic investigators and researchers formulate region-specific regression equations for PMSI estimation.

Effects of aluminium phosphide on larval morphometry of two important Chrysomya species.

Chrysomya megacephala and C. rufifacies are globally predominant species of blowflies that are amongst the primary colonisers of decomposing carcasses. The development of blowflies has been studied extensively to estimate the minimum postmortem interval (PMImin). This article evaluates the effect of aluminium phosphide (AlP) on the larval morphometry and life cycles of C. megacephala and C. rufifacies. The rabbits were given different dosages of AlP and their livers were excised to rear C. megacephala and C. rufifacies. Through multiple-regression analysis, we assessed the overall impact of varying dosages of AlP on larvae of both species. AlP accelerated development until pupation, whilst the time until emergence remained the same. At higher concentrations, AlP had a positive effect on the development of these species. Since both species are abundant, forensic entomology studies examining the effect of AlP on morphometry and developmental stages would provide valuable information to investigators assessing PMImin.

The implication of morphometrics and growth rate of dipteran flies in forensic entomotoxicology research: a review.

Forensic entomotoxicology integrates toxicology into forensic entomology to estimate minimum postmortem interval (PMImin) and circumstances of death where toxicants and poisonous substances are the suspected cause of death. Forensic entomotoxicology not only confirms the presence of toxicants in insects feeding off a cadaver but also studies its effect on the bio-morphometry and growth rate of insects. This review article highlights the effects of various toxicants on forensically important species of dipteran flies. It also discusses the parameters that may affect accuracy in estimation of time since death. The bio-physical effects of toxicants (excluding the analytical approach for qualitative detection) would help understand the trends in forensic entomotoxicological research worldwide.

Seasonal study of the decomposition pattern and insects on a submerged pig cadaver.

Research on studying the decomposition pattern in aquatic habitat is very sparse worldwide. Due to this void, assessment of the postmortem submersion interval (PMSI) of drowned and submerged cadavers is still inaccurate and imprecise. The current work focused on studying the decomposition pattern and insects associated with submerged pig (Sus scrofa) carcasses during various seasons (winter, spring, summer, and rainy) for two years. The total postmortem submersion interval (PMSI) from the fresh stage till the sunken remains stage varied from 25 days for rainy season (624.5 ADD) to 78 days (1890.5 ADD) for winter season. The spring season at 44 days (1067.5 ADD) and summer season at 31 days (763.5 ADD) had moderate PMSI. During this time interval, five stages of decomposition were studied: submerged fresh, early floating, floating decay, advanced floating decay, and sunken remains. A total of 2385 insect specimens were found to be associated with different decomposition stages. The terrestrial activity during the first stage (submerged fresh) was almost nil as the carcasses were submerged. During the early floating stage (2nd stage), various terrestrial insect species visited the carcass and laid their eggs along with the presence of Chironomidae, Coenagrionidae, Lestidae, Aeshnidae families (order Odonata) were also found associated with this stage. In the floating decay (3rd stage), the insects visiting and colonizing the carcass were from Coenagrionidae, Gomphidae, Aeshnidae, Gomphidae, Libellulidae Chironomidae (Order-Odonata) families along with Calliphoridae (order- Diptera). Species from the group of scavenging aquatic beetles (Hydrophilidae), Enochrus esuriens (Walker), Regimbartia attenuata (Fab), Helochares sp. and burrowing water beetles, Canthydrus laetabilis (Family: Noteridae) and some terrestrial species of beetles, i.e. Saprinus sp., Saprinus pensylvenicus and Necrobia rufipus (Family: Cleridae) were also present during the 3rd, 4th and 5th stages. During advanced floating decay (4th stage) and sunken remains (5th stage), many hemipteran species such as Ranatra digitata and Ranatra filiformis (Fab) along with many coleopterans were found visiting the corpse.

Data on haplotype diversity in the hypervariable region I, II and III of mtDNA amongst the Brahmin population of Haryana.

Human mitochondrial DNA (mtDNA) is routinely analysed for pathogenic mutations, evolutionary studies, estimation of time of divergence within or between species, phylogenetic studies and identification of degraded remains. The data on various regions of human mtDNA has added enormously to the knowledge pool of population genetics as well as forensic genetics. The displacement-loop (D-loop) in the control region of mtDNA is rated as the most rapidly evolving part, due to the presence of variations in this region. The control region consists of three hypervariable regions. These hypervariable regions (HVI, HVII and HVIII) tend to mutate 5-10 times faster than nuclear DNA. The high mutation rate of these hypervariable regions is used in population genetic studies and human identity testing. In the present data, potentially informative hypervariable regions of mitochondrial DNA (mtDNA) i.e. HVI (np 16024-16365), HVII (np 73-340) and HVIII (np 438-576) were estimated to understand the genetic diversity amongst Brahmin population of Haryana. Blood samples had been collected from maternally unrelated individuals from the different districts of Haryana. An array of parameters comprising of polymorphic sites, transitions, transversions, deletions, gene diversity, nucleotide diversity, pairwise differences, Tajima's D test, Fu's Fs test, mismatch observed variance and expected heterozygosity were estimated. The observed polymorphisms with their respective haplogroups in comparison to rCRS were assigned.

Sequence polymorphism data of the hypervariable regions of mitochondrial DNA in the Yadav population of Haryana.

Genetic variations among humans occur both within and among populations and range from single nucleotide changes to multiple-nucleotide variants. These multiple-nucleotide variants are useful for studying the relationships among individuals or various population groups. The study of human genetic variations can help scientists understand how different population groups are biologically related to one another. Sequence analysis of hypervariable regions of human mitochondrial DNA (mtDNA) has been successfully used for the genetic characterization of different population groups for forensic purposes. It is well established that different ethnic or population groups differ significantly in their mtDNA distributions. In the last decade, very little research has been conducted on mtDNA variations in the Indian population, although such data would be useful for elucidating the history of human population expansion across the world. Moreover, forensic studies on mtDNA variations in the Indian subcontinent are also scarce, particularly in the northern part of India. In this report, variations in the hypervariable regions of mtDNA were analyzed in the Yadav population of Haryana. Different molecular diversity indices were computed. Further, the obtained haplotypes were classified into different haplogroups and the phylogenetic relationship between different haplogroups was inferred.

Data of drowning related deaths with reference to entomological evidence from Haryana.

Most often the newspapers and bulletin come out with voluminous cases of deaths due to drowning. At the same time an ample section of such cases encompass entomological evidences, that can be scrutinized as a very useful parameter in estimating post mortem interval (PMI). This research database is an outcome of a 2 years reflective study, based on an assessment of records related to human deaths due to drowning. The drowned bodies from various districts of Haryana are sent to PGIMS (Post Graduate Institute of Medical Sciences), Rohtak. The study took the data of year 2015-2016 into consideration. All the cases were reviewed and summarized in terms of monthly occurrence of total cases, age differentiation, gender differentiation and month wise occurrence of entomological evidences on the dead bodies through detailed study of post mortem findings. This data will lead to an insight into the magnitude of drowning deaths in Haryana along with the usage of entomological data for determining Post Mortem Submersion Intervals (PMSI).