Efficient DNA Sampling in Burglary Investigations

In terms of crime scene investigations by means of forensic DNA-analyses, burglaries are the number one mass crime in Switzerland. Around one third of the DNA trace profiles registered in the Swiss DNA database are related to burglaries. However, during the collection of potential DNA traces within someone’s residence after a burglary, it is not known whether the sampled DNA originated from the perpetrator or from an inhabitant of said home. Because of the high incidence of burglaries, crime scene investigators usually do not collect reference samples from all the residents for economical and administrative reasons. Therefore, the presumably high probability that a DNA profile belonging to a person authorized to be at the crime scene ends up being sent to a DNA database for comparison, has to be taken into account. To our knowledge, no investigation has been made to evaluate the percentage of these non-perpetrator profiles straying into DNA databases. To shed light on this question, we collected reference samples from residents who had been victims of recent burglaries in their private homes. By comparing the profiles established from these reference samples with the profiles generated from trace DNA, we can show that the majority of the DNA samples collected in burglary investigations belong to the residents. Despite the limited number of cases included in the study, presumably due to a crime decline caused by the pandemic, we further show that trace DNA collection in the vicinity of the break and entry area, in particular window and door glasses, is most promising for sampling perpetrator instead of inhabitant DNA.

Mitochondrial Genetic Diversity, Population Structure and Detection of Antillean and Amazonian Manatees in Colombia: New Areas and New Techniques

The Antillean manatee (Trichechus manatus) and the Amazonian manatee (Trichechus inunguis) are distributed in rivers in the Caribbean and Amazonian region of Colombia respectively. For 30 years, genetic information has been obtained from these populations in order to inform conservation programs for these endangered species and decide on the location to release them back to the wild. However, in previous studies, samples from rivers in some areas of the country were not included, given the difficulties to access these regions due to either logistic or safety issues. In this study, we analyzed mitochondrial DNA (mtDNA) control region (CR) sequences of from samples of T. manatus (n = 37) and T. inunguis (n = 4) (410 and 361 bp, respectively), obtained in new and previously unexplored rivers and bays in the country, including Santa Marta, Urabá Gulf, Ayapel Marsh (San Jorge River Basin), Meta River and Magdalena Medio and the low Magdalena River (Cesar Province and Canal del Dique) as well as additional samples from Puerto Nariño in the Colombian Amazon. Our results included the discovery of two newly described mtDNA CR haplotypes for T. manatus. In addition, we confirmed significant population differentiation at the mitochondrial level between the Magdalena and Sinú rivers and differentiation among areas of the same river, including the middle and low Magdalena River. This differentiation may be related to anthropic changes in the river since construction of the Canal del Dique in the XVI century. We also tested environmental DNA sampling and analyses techniques to evaluate its potential use for manatee detection and monitoring in bodies of water in Colombia, in order to evaluate new areas for future manatee conservation initiatives. We emphasize the need to continue using genetic information to provide evidence on the potential best locations to undertake animal release to prevent outbreeding depression.

Environmental DNA sampling protocols for the surveillance of marine non-indigenous species v3

This document describes a series of protocols for the collection of environmental samples intended for the monitoring and surveillance of marine invasive species by means of eDNA metabarcoding analysis, as described in the associated publication (Fernandez et al. 2021: https://doi.org/10.1016/j.marpolbul.2021.112893).

The Foster method: Rapid and non-invasive detection of clinically relevant American Foulbrood disease levels using eDNA sampling and a dual-target qPCR assay, with its potential for other hive pathogens.

Clinical signs of American Foulbrood can be difficult to diagnose and thus disease is missed and leads to further spread. Diagnosis is centred on the beekeeper's skill in recognising clinical symptoms – a highly subjective and time-consuming activity. Previous testing methods have relied on sampling that necessitates dismantling the hive and/or requires multiple visits to retrieve passive samples. The Foster method is a new environmental DNA sampling method using entrance swabs together with a dual-target qPCR for AFB. The quantification data generated can be used to detect hives with clinically relevant infections, even when no visual symptoms are apparent. Such a method will be applicable to other bee pathogens and incursion pests.

Detection of Jaguar (Panthera onca) From Genetic Material in Drinking Water

Jaguar (Panthera onca) are of conservation concern and occur at very low densities in the northern portion of their range in northern Mexico and the southwestern United States. Environmental DNA sampling to detect genetic material from drinking water may be an effective approach for jaguar detection in these arid landscapes. Here we develop a qPCR assay for the detection of jaguar mitochondrial DNA, show that large quantities of DNA (mean 66,820 copies/L) can be found in the drinking water of captive animals, and observe detectable levels of DNA (80 copies/L) in a wild habitat with known jaguar populations. We suggest that environmental DNA sampling may represent a useful, complementary sampling tool for detection of rare jaguars, although effective application would require careful consideration of DNA persistence time in the environment.

The Use of Bone Fluorescence to Facilitate DNA Sampling

DNA is increasingly used in skeletal remains cases for identification and to resolve commingling. The implementation of a sampling strategy based on the likelihood of obtaining viable DNA profiles could minimize destruction of bones, expedite identification, and save time and resources by reducing the need to resample. Here we test whether bone fluorescence is a good indicator of potential DNA yield. Samples consisted of remains from seven different burial sites analyzed by the Committee on Missing Persons in Cyprus Anthropological Laboratory that were submitted for DNA analysis to an external DNA laboratory. Fluorescence was assessed as a function of pixel brightness values using images of bone and tooth samples captured using an alternate light source and measured in ImageJ. Across seven pooled sites, no relationship was apparent between fluorescence and DNA extracted, but there was a positive relationship when certain sites were considered in isolation. These results appear to suggest no overall relationship between fluorescence and DNA extracted; however, given the mixed nature of these results, additional research using a more controlled sample is needed.