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A significant hurdle for the widespread implementation and use of synthetic biology is the challenge of highly efficient introduction of DNA into microorganisms. This is especially a barrier for the utilization of non-model organisms and/or novel chassis species for a variety of applications, ranging from molecular biology to biotechnology and biomanufacturing applications. Common approaches to episomal and chromosomal gene editing, which employ techniques such as chemical competence and electroporation, are typically only amenable to a small subset of microbial species while leaving the vast majority of microorganisms in nature genetically inaccessible. To address this challenge, we have employed the previously described B. subtilis broad-host conjugation strain, XPORT, which was modularly designed for loading DNA cargo and conjugating such DNA into recalcitrant microbes. In this current work, we have leveraged and adapted the XPORT strain for use in a droplet microfluidic platform to enable increased efficiency of conjugation-based DNA transfer. The system named DNA ENTRAP (DNA ENhanced TRAnsfer Platform) utilizes cell-encapsulated water-in-oil emulsion droplets as pico-liter-volume bioreactors that allows controlled contacts between the donor and receiver cells within the emulsion bioreactor. This allowed enhanced XPORT-mediated genetic transfer over the current benchtop XPORT process, demonstrated using two different Bacillus subtilis strains (donor and receiver), as well as increased throughput (e.g., number of successfully conjugated cells) due to the automated assay steps inherent to microfluidic lab-on-a-chip systems. DNA ENTRAP paves the way for a streamlined automation of culturing and XPORT-mediated genetic transfer processes as well as future high-throughput cell engineering and screening applications. • Developed a droplet microfluidic device (DNA ENTRAP) for microbial engineering. • Demonstrated horizontal gene transfer efficiency increases over 200%. • Encapsulation of donor and recipient in a microdroplet enhances gene transfer. • Microfluidic-adapted SynBio tool for the domestication of untapped microbes. [ABSTRACT FROM AUTHOR]

Biological invasions have been identified as the fifth cause of biodiversity loss, and their subsequent dispersal represents a major ecological challenge. The aquatic invasive species Ludwigia grandiflora subsp. hexapetala (Lgh) and Ludwigia peploides subsp. montevidensis (Lpm) are largely distributed in aquatic environments in North America and in Europe. However, they also present worrying terrestrial forms that are able to colonize wet meadows. To comprehend the mechanisms of the terrestrial adaptation of Lgh and Lpm, it is necessary to develop their genomic resources, which are currently poorly documented. We performed de novo assembly of the mitogenomes of Lgh and Lpm through hybrid assemblies, combining short reads (SR) and/or long reads (LR) before annotating both mitogenomes. We successfully assembled the mitogenomes of Lgh and Lpm into two circular molecules each, resulting in a combined total length of 711,578 bp and 722,518 bp, respectively. Notably, both the Lgh and Lpm molecules contained plastome-origin sequences, comprising 7.8% of the mitochondrial genome length. Additionally, we identified recombinations that were mediated by large repeats, suggesting the presence of multiple alternative conformations. In conclusion, our study presents the first high-quality mitogenomes of Lpm and Lgh, which are the only ones in the Myrtales order found as two circular molecules. [ABSTRACT FROM AUTHOR]

Adhesive tape is a common piece of evidence that can contain a myriad of traces. Due to its adhesive properties, adhesive tape can potentially collect traces unrelated to the crime or relocate crime-relevant traces. This secondary transfer of traces can have crucial implications for the evaluation at the activity level. Therefore, this study investigated the secondary transfer of DNA between layers of adhesive tape and tape and other case- and laboratory-relevant substrates. A drop of diluted blood was deposited on different primary substrates (i.e. duct tape, metal, plastic, textile, nitrile gloves). Subsequently, the primary substrate was brought into contact with a secondary substrate, and DNA was collected from both surfaces to measure transfer rates. The highest transfer rates were detected between the adhesive side of the tape and plastic, whereas the lowest transfer rates were detected between the adhesive side and textile. It was shown that the adhesive readily collects DNA from plastic and nitrile gloves commonly used in the laboratory, which highlights the importance of working with DNA-free materials. Therefore, this study demonstrated the need for caution when interpreting traces on adhesive tapes, always taking possible situations of secondary transfer into account. [ABSTRACT FROM AUTHOR]

It is important to have an awareness of the factors that may impact DNA transfer. Here we perform a preliminary study on the impact of airflow on the transfer of DNA from biological materials. Common airflows at different distances from their source were determined. Biological materials on different substrates were exposed to relatively high airflows. Tests showed that airflow can transfer detectable levels of DNA away from where they were deposited, especially blood, less so saliva and touch DNA. Information on indirect transfer of biological materials due to airflow can assist activity level evaluations and considerations towards improvements in laboratory design and procedures. [ABSTRACT FROM AUTHOR]

Face touching is a common habit that can have implications on the outcome of criminal investigations. When conducting activity level assessments, it is important to be aware of any factors that may impact the type of profile obtained from the sample of interest. This may include the number, duration, location, and manner of contacts that a person makes with themselves. In this study we have recorded the contacts made by different individuals, of their hands with their face, over a 1 hr period, while working within an office. All participants were observed to regularly touch their face. Swabs of the face of some participants were subsequently collected for DNA profiling. The individuals sampled were found to be the sole or majority contributor to the profiles generated. [ABSTRACT FROM AUTHOR]

Abstract Background Orchardgrass (Dactylis glomerata L.), a perennial forage, has the advantages of rich leaves, high yield, and good quality and is one of the most significant forage for grassland animal husbandry and ecological management in southwest China. Mitochondrial (mt) genome is one of the major genetic systems in plants. Studying the mt genome of the genus Dactylis could provide more genetic information in addition to the nuclear genome project of the genus. Results In this study, we sequenced and assembled two mitochondrial genomes of Dactylis species of D. glomerata (597, 281 bp) and D. aschersoniana (613, 769 bp), based on a combination of PacBio and Illumina. The gene content in the mitochondrial genome of D. aschersoniana is almost identical to the mitochondrial genome of D. glomerata, which contains 22–23 protein-coding genes (PCGs), 8 ribosomal RNAs (rRNAs) and 30 transfer RNAs (tRNAs), while D. glomerata lacks the gene encoding the Ribosomal protein (rps1) and D. aschersoniana contains one pseudo gene (atp8). Twenty-three introns were found among eight of the 30 protein-coding genes, and introns of three genes (nad 1, nad2, and nad5) were trans-spliced in Dactylis aschersoniana. Further, our mitochondrial genome characteristics investigation of the genus Dactylis included codon usage, sequences repeats, RNA editing and selective pressure. The results showed that a large number of short repetitive sequences existed in the mitochondrial genome of D. aschersoniana, the size variation of two mitochondrial genomes is due largely to the presence of a large number of short repetitive sequences. We also identified 52–53 large fragments that were transferred from the chloroplast genome to the mitochondrial genome, and found that the similarity was more than 70%. ML and BI methods used in phylogenetic analysis revealed that the evolutionary status of the genus Dactylis. Conclusions Thus, this study reveals the significant rearrangements in the mt genomes of Pooideae species. The sequenced Dactylis mt genome can provide more genetic information and improve our evolutionary understanding of the mt genomes of gramineous plants.

Background: Orchardgrass (Dactylis glomerata L.), a perennial forage, has the advantages of rich leaves, high yield, and good quality and is one of the most significant forage for grassland animal husbandry and ecological management in southwest China. Mitochondrial (mt) genome is one of the major genetic systems in plants. Studying the mt genome of the genus Dactylis could provide more genetic information in addition to the nuclear genome project of the genus. Results: In this study, we sequenced and assembled two mitochondrial genomes of Dactylis species of D. glomerata (597, 281 bp) and D. aschersoniana (613, 769 bp), based on a combination of PacBio and Illumina. The gene content in the mitochondrial genome of D. aschersoniana is almost identical to the mitochondrial genome of D. glomerata, which contains 22–23 protein-coding genes (PCGs), 8 ribosomal RNAs (rRNAs) and 30 transfer RNAs (tRNAs), while D. glomerata lacks the gene encoding the Ribosomal protein (rps1) and D. aschersoniana contains one pseudo gene (atp8). Twenty-three introns were found among eight of the 30 protein-coding genes, and introns of three genes (nad 1, nad2, and nad5) were trans-spliced in Dactylis aschersoniana. Further, our mitochondrial genome characteristics investigation of the genus Dactylis included codon usage, sequences repeats, RNA editing and selective pressure. The results showed that a large number of short repetitive sequences existed in the mitochondrial genome of D. aschersoniana, the size variation of two mitochondrial genomes is due largely to the presence of a large number of short repetitive sequences. We also identified 52–53 large fragments that were transferred from the chloroplast genome to the mitochondrial genome, and found that the similarity was more than 70%. ML and BI methods used in phylogenetic analysis revealed that the evolutionary status of the genus Dactylis. Conclusions: Thus, this study reveals the significant rearrangements in the mt genomes of Pooideae species. The sequenced Dactylis mt genome can provide more genetic information and improve our evolutionary understanding of the mt genomes of gramineous plants. [ABSTRACT FROM AUTHOR]

The ability to detect low level DNA brings with it the uncertainty of whether the detected DNA is a result of transfer. To address this uncertainty, a simulation study was conducted in which a mock illicit drug packet was placed into the personal bags of individuals. When the average transit time of the packets was increased from around 2 h to more than 14 h, the percentage of the DNA profiles recovered from the packets which could be attributed to the individuals increased greatly from 5.3% to 48.6%. We found that drug packers who were poor shedders could not be included as contributors to the DNA profiles from the drug packets at all and there was a higher chance that individuals other than themselves could be included as contributors to the DNA profile recovered from drug packets. We also found that it was equally likely that the drug packers who had direct contact with the drug packets and bag owners who did not, could be included as contributors to the DNA profiles recovered from the packets. The results in this study highlight the importance of taking into consideration the transit time of drug packet, the shedder status of the alleged packer and the history of an item, when evaluating DNA evidence in the context of illicit drug activities. [ABSTRACT FROM AUTHOR]

• DNA recovered from regularly-worn jumpers before and after use by a second wearer. • When worn by one wearer, most samples gave major or single-source profile of wearer. • After second wearer, reproducible profile compositions varied between pairings. • Shedder status affected DNA quantities and profile compositions between wearers. • Neither recovery method nor sampling location impacted DNA profile composition. Items of worn clothing are routinely examined for DNA in forensic casework, commonly with the expectation that at least some of the DNA will come from a wearer of the item, so-called 'wearer DNA'. This study investigated DNA recovered from hooded jumpers that were regularly worn and laundered for four weeks and then subsequently worn by a different individual for four hours. This study also systematically investigated whether using different recovery methods or sampling locations on the jumpers might distinguish between DNA deposited by the regular and most recent wearers of clothing. Four volunteers each wore a new hooded jumper regularly (6 h/day, 2 days/week, washed at weekends) during two 4-week periods. At the end of each month, DNA was first recovered by cutting out and mini-taping the inside left cuff, half-collar, pocket and underarm fabric. The jumpers were then worn by a different individual for four hours, and DNA was again recovered by cutting out and mini-taping, but this time from the inside right cuff, half-collar, pocket and underarm fabric. All DNA samples (n = 128) were quantified and profiled. DNA quantities ranged from 0 to ∼40 ng with an outlier of ∼150 ng, and no significant differences were observed among recovery methods and sampling locations, nor whether one or two wearers had worn the jumpers. However, one volunteer consistently deposited significantly more DNA to their jumpers than two other volunteers, confirming the impact of 'shedder status' on DNA deposition during wearing of clothing. When jumpers were regularly worn by one wearer, the majority (72.7–83.3 %) of the samples for all wearers across both months comprised a major profile of the wearer with a minor profile of non-wearer alleles. When jumpers were then worn by a second wearer, the composition of the profiles obtained were generally reproducible across the recovery methods used, the sampling locations and the two replicates of the experiment for each pairing of wearers. However, profile compositions differed between wearer pairings. Overall, ∼60 % of profiles obtained gave a major profile of the regular wearer, whereas ∼30 % gave a major profile of the second wearer. The remaining profiles comprised other much less frequent observations of single-source profiles of each wearer and equal proportions of DNA from both wearers. Non-wearer DNA was also observed in the majority of samples, both before and after jumpers were worn by a second wearer. For one volunteer's jumpers, a recurring non-wearer DNA profile was observed that could be attributed to their romantic partner, and this DNA persisted on the jumpers even after being worn by the second wearer. This study provides insight on the impact of shedder status, multiple wearers, different recovery methods and sampling locations on the quantities of DNA and compositions of DNA profiles recovered from authentically regularly-worn hooded jumpers. The findings also provide a preliminary dataset that can be used to infer activity level probabilities in casework. [ABSTRACT FROM AUTHOR]

The presence of background DNA (bgDNA) can hinder the evaluation of DNA evidence at the activity level, especially when the suspect is expected to be retrieved due to their habitual occupation of the investigated environment. Based on real-life casework circumstances, this study investigates the prevalence, composition, origin, and probable transfer routes of bgDNA found on personal items in situations where their owner and person of interest (POI) share the same workspace. Baseline values of bgDNA were evaluated on the participants' personal items. Secondary and higher degree transfer scenarios of non-self DNA deposition were also investigated. The DNA from co-workers and co-inhabiting partners can be recovered from an individual's personal belongings. Non-self DNA present on the hands and deposited on a sterile surface can generate uninformative profiles. The accumulation of foreign DNA on surfaces over time appears to be crucial for the recovery of comparable profiles, resulting in detectable further transfer onto other surfaces. For a thorough evaluation of touch DNA traces at the activity level, it is necessary to collect information not only about DNA transfer probabilities but also about the presence of the POI as part of the 'baseline' bgDNA of the substrates involved. [ABSTRACT FROM AUTHOR]

Paeonia lactiflora (P. lactiflora), a perennial plant renowned for its medicinal roots, provides a unique case for studying the phylogenetic relationships of species based on organelle genomes, as well as the transference of DNA across organelle genomes. In order to investigate this matter, we sequenced and characterized the mitochondrial genome (mitogenome) of P. lactiflora. Similar to the chloroplast genome (cpgenome), the mitogenome of P. lactiflora extends across 181,688 base pairs (bp). Its unique quadripartite structure results from a pair of extensive inverted repeats, each measuring 25,680 bp in length. The annotated mitogenome includes 27 protein-coding genes, 37 tRNAs, 8 rRNAs, and two pseudogenes (rpl5, rpl16). Phylogenetic analysis was performed to identify phylogenetic trees consistent with Paeonia species phylogeny in the APG Ⅳ system. Moreover, a total of 12 MTPT events were identified and 32 RNA editing sites were detected during mitogenome analysis of P. lactiflora. Our research successfully compiled and annotated the mitogenome of P. lactiflora. The study provides valuable insights regarding the taxonomic classification and molecular evolution within the Paeoniaceae family. [ABSTRACT FROM AUTHOR]

Pets, such as cats and dogs, are present in the majority of households and may, in certain circumstances, be a relevant element in criminal investigations. Dogs, in particular, may interact with an intruder resulting in an exchange of trace evidence between the two. To better understand these interactions, fifty videos of dog contacts with an intruder were analysed, noting the location and the type of an interaction. It was found that dogs were more likely to instigate the interaction, jumping on the intruder, and were most commonly contacted on the head and back. [ABSTRACT FROM AUTHOR]

DNA recovery from fired cartridge cases (FCCs) remains challenging due to the limited DNA amounts available for collection, hence efforts to retain the available DNA are essential. Here we use DiamondTM nucleic acid dye staining to show that DNA may be lost from an FCC to the inside of its packaging after collection at a crime scene. A novel cartridge collection device mitigated this DNA loss under the conditions tested and could be beneficial for casework. [ABSTRACT FROM AUTHOR]

In sexual assault cases, the retrieved DNA quantity and sampling location from the victim's underwear may provide valuable information for activity level evaluative reporting. DNA can transfer from site to site on an exhibit, or be lost within packaging, complicating interpretation. Experiments are needed to investigate these factors. This preliminary study compared two cleaning methods to prepare undergarments for such experimentation: hand-washing with warm water and washing with bleach before rinsing. Results show a significantly lower quantity of DNA on washed underwear using both methods. Warm-water hand-washing, the more straightforward method, was selected for further experimentation. [ABSTRACT FROM AUTHOR]

Biological invasions have been identified as the fifth cause of biodiversity loss, and their subsequent dispersal represents a major ecological challenge. The aquatic invasive species Ludwigia grandiflora subsp. hexapetala (Lgh) and Ludwigia peploides subsp. montevidensis (Lpm) are largely distributed in aquatic environments in North America and in Europe. However, they also present worrying terrestrial forms that are able to colonize wet meadows. To comprehend the mechanisms of the terrestrial adaptation of Lgh and Lpm, it is necessary to develop their genomic resources, which are currently poorly documented. We performed de novo assembly of the mitogenomes of Lgh and Lpm through hybrid assemblies, combining short reads (SR) and/or long reads (LR) before annotating both mitogenomes. We successfully assembled the mitogenomes of Lgh and Lpm into two circular molecules each, resulting in a combined total length of 711,578 bp and 722,518 bp, respectively. Notably, both the Lgh and Lpm molecules contained plastome-origin sequences, comprising 7.8% of the mitochondrial genome length. Additionally, we identified recombinations that were mediated by large repeats, suggesting the presence of multiple alternative conformations. In conclusion, our study presents the first high-quality mitogenomes of Lpm and Lgh, which are the only ones in the Myrtales order found as two circular molecules.

The combined approach of classical fingerprinting and DNA profiling is a powerful tool in forensic investigations of latent "touch" traces. However, little attention has been paid to the organic solvents frequently used in dactyloscopic laboratories to facilitate the separation of adhesive evidence prior to fingerprint development and downstream effects on subsequent DNA profiling. In the present study, we tested a selection of adhesive removers (n = 9) and assessed their potential impact on DNA recovery and amplification by PCR. Thereby, we identified and characterized novel PCR inhibitors. All investigated chemicals contain volatile organic compounds that evaporate under normal indoor atmospheric conditions. Exposure to certain solvents resulted in increased DNA degradation, but only if evaporation was prevented. A series of adhesive-removal experiments were conducted with prepared mock evidence (self-adhesive postage stamps affixed to paper envelope) to investigate the impact of treatment time and the location of applied traces on DNA recovery and dactyloscopy, respectively. Due to the early onset of print decomposition, we found that only a short treatment time was compatible with the development of fingerprints on the adhesive side of a stamp. Solvents also removed DNA from the adhesive surface, thus resulting in a marked shift in the substrate distribution of recovered DNA from the stamp to the envelope, but not in the reverse direction. Furthermore, we observed that treatment with conventional fingerprint reagents lead to a significant reduction in the amounts of DNA recovered from stamps, while the additional use of adhesive removers did not significantly enhance this effect. [ABSTRACT FROM AUTHOR]

The shedder status of a person is an important consideration when evaluating probabilities of DNA transfer during activity‐level assessments. As an extension of our previously published study, the shedder statuses of 38 individuals were reassessed 1 year later. The study found that shedder status may change over time for some individuals and was associated with one's gender, number of items touched, and mobile phone usage. In 29% of touch events, no DNA allele was detected and in 99% of touch events, the amount of DNA deposited was <2 ng. The study also found that in 0.6% of touch events, the participant could be excluded as a contributor of the observed DNA profile, with another person being included. Additionally, our investigations suggest that the current three‐category system for shedder status classification may require further refinement to better represent the individuals' shedder status in a population. [ABSTRACT FROM AUTHOR]

Awareness of the factors surrounding the transfer of DNA from a person, item, or surface to another person, item, or surface is highly relevant during investigations of alleged criminal activity. Animals in domestic environments could be a victim, offender, or innocent party associated with a crime. There is, however, very limited knowledge of human DNA transfer, persistence, prevalence, and recovery (DNA TPPR) associated with domestic animals. This pilot study aimed to improve our understanding of DNA TPPR associated with domestic dogs by collecting and analysing samples from various external areas of dogs of various breeds, interactions with humans, and living arrangements, and conducting a series of tests to investigate the possibility of dogs being vectors for the indirect transfer of human DNA. Reference DNA profiles from the dog owners and others living in the same residence were acquired to assist interpretation of the findings. The findings show that human DNA is prevalent on dogs, and in the majority of samples, two-person mixtures are present. Dogs were also found to be vectors for the transfer of human DNA, with DNA transferred from the dog to a gloved hand during patting and a sheet while walking. [ABSTRACT FROM AUTHOR]

• The study includes 28 donors that had refrained from sexual activity for 24 h prior to the study. • 56 swabs; one wet and one dry from the shaft of each donor's penis, and 28 pairs of underpants. • Testing for visible blood by Kastle Meyer (KM) or leuco-malachite green (LMG) methods. • Tests for presence of semen and saliva used acid phosphatase and α-amylase. • Extremely informative results for cases of alleged sexual assault. This study examines the background of blood, saliva, semen and autosomal DNA on penile swabs and underpants from males in the absence of recent sexual activity. Based on the data collected by the AFSP Body Fluid Forum, the results of this study show that; there is a very low expectation of detecting blood on penile swabs and male underpants; a low expectation of detecting saliva on penile swabs and male underpants; and spermatozoa would be expected in less than a quarter of penile swabs and three quarters of male underpants. As none of the samples had detectable levels of DNA which were suitable for meaningful comparison that did not match the donor or their partner, the expectation of detecting a DNA profile from the cellular background on penile swabs or underpants from a male who has not been involved in recent sexual intercourse is very low. The results of this study are extremely informative when evaluating the significance of blood, saliva, semen and DNA detected on the penile swabs and underpants of males in cases of alleged sexual assault. [ABSTRACT FROM AUTHOR]

Paeonia lactiflora (P. lactiflora), a perennial plant renowned for its medicinal roots, provides a unique case for studying the phylogenetic relationships of species based on organelle genomes, as well as the transference of DNA across organelle genomes. In order to investigate this matter, we sequenced and characterized the mitochondrial genome (mitogenome) of P. lactiflora. Similar to the chloroplast genome (cpgenome), the mitogenome of P. lactiflora extends across 181,688 base pairs (bp). Its unique quadripartite structure results from a pair of extensive inverted repeats, each measuring 25,680 bp in length. The annotated mitogenome includes 27 protein-coding genes, 37 tRNAs, 8 rRNAs, and two pseudogenes (rpl5, rpl16). Phylogenetic analysis was performed to identify phylogenetic trees consistent with Paeonia species phylogeny in the APG Ⅳ system. Moreover, a total of 12 MTPT events were identified and 32 RNA editing sites were detected during mitogenome analysis of P. lactiflora. Our research successfully compiled and annotated the mitogenome of P. lactiflora. The study provides valuable insights regarding the taxonomic classification and molecular evolution within the Paeoniaceae family.

The presence of background DNA (bgDNA) can hinder the evaluation of DNA evidence at the activity level, especially when the suspect is expected to be retrieved due to their habitual occupation of the investigated environment. Based on real-life casework circumstances, this study investigates the prevalence, composition, origin, and probable transfer routes of bgDNA found on personal items in situations where their owner and person of interest (POI) share the same workspace. Baseline values of bgDNA were evaluated on the participants’ personal items. Secondary and higher degree transfer scenarios of non-self DNA deposition were also investigated. The DNA from co-workers and co-inhabiting partners can be recovered from an individual’s personal belongings. Non-self DNA present on the hands and deposited on a sterile surface can generate uninformative profiles. The accumulation of foreign DNA on surfaces over time appears to be crucial for the recovery of comparable profiles, resulting in detectable further transfer onto other surfaces. For a thorough evaluation of touch DNA traces at the activity level, it is necessary to collect information not only about DNA transfer probabilities but also about the presence of the POI as part of the ‘baseline’ bgDNA of the substrates involved.

Investigations of unlawful use of motor vehicle (UUMV) offences often rely on detection of the offender's DNA inside the vehicle. Steering wheels are likely to retain the DNA of a recent driver; however, they often recover insufficient DNA for forensic DNA profiling or complex mixed DNA profiles unsuitable for comparison. In contrast, samples taken from the driver's side seat often included the recent driver's profile, with less DNA from other individuals. Further, in warmer climates, offenders are likely to dress in lightweight clothing, including shorts, which increases skin contact with car seats, particularly during the warmer months. Thus, to test the suitability of sampling car seats in comparison with steering wheels in a casework context, we employed a paired sampling approach to every suitable vehicle examined by forensic officers in a tropical Australian regional city over a six-month period. There was a significant difference between the overall DNA sampling results from car seats and steering wheels; however, there was little difference in the numbers of uploadable profiles or offender identifications between the sampled areas. These data contribute substantially to our knowledge of DNA transfer under real-world conditions and inform operational practices aimed at maximizing evidence recovery from crime scenes. [ABSTRACT FROM AUTHOR]

Abstract Background Saposhnikovia divaricata (Turcz.) Schischk. is a perennial herb whose dried roots are commonly used as a source of traditional medicines. To elucidate the organelle-genome-based phylogeny of Saposhnikovia species and the transfer of DNA between organelle genomes, we sequenced and characterised the mitochondrial genome (mitogenome) of S. divaricata. Results The mitogenome of S. divaricata is a circular molecule of 293,897 bp. The nucleotide composition of the mitogenome is as follows: A, 27.73%; T, 27.03%; C, 22.39%; and G, 22.85. The entire gene content is 45.24%. A total of 31 protein-coding genes, 20 tRNAs and 4 rRNAs, including one pseudogene (rpl16), were annotated in the mitogenome. Phylogenetic analysis of the organelle genomes from S. divaricata and 10 related species produced congruent phylogenetic trees. Selection pressure analysis revealed that most of the mitochondrial genes of related species are highly conserved. Moreover, 2 and 46 RNA-editing sites were found in the chloroplast genome (cpgenome) and mitogenome protein-coding regions, respectively. Finally, a comparison of the cpgenome and the mitogenome assembled from the same dataset revealed 10 mitochondrial DNA fragments with sequences similar to those in the repeat regions of the cpgenome, suggesting that the repeat regions might be transferred into the mitogenome. Conclusions In this study, we assembled and annotated the mitogenome of S. divaricata. This study provides valuable information on the taxonomic classification and molecular evolution of members of the family Apiaceae.

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This study aimed to identify if biological material could be detected on the opposite side to deposition on fabric by commonly used presumptive and/or secondary tests. Additionally, this study aimed to ascertain if there is a difference in the DNA quantity and quality from samples obtained from both sides of the same substrate: cotton, polyester, denim, or combined viscose and polyester swatches. Blood, semen, or saliva (25 μL) was deposited on one side of 5 replicates of each fabric type and left for 24 h. Blood swatches were tested using Hemastix® and the ABACard® HemaTrace® immunoassay, semen swatches were tested using acid phosphatase (AP) reagent, the ABACard® p30® immunoassay and hematoxylin and eosin staining, and saliva swatches were tested using Phadebas® paper and the RSID-Saliva™ immunoassay. Both sides of each swatch were separately wet/dry swabbed and subjected to DNA analysis. Blood was able to be detected on the underside of all fabrics using both tests. Semen was able to be detected on the underside of swatches using the presumptive AP test but not p30®, and sperm was rarely observed. Saliva was able to be detected by RSID-Saliva™ but not Phadebas® paper when the underside of swatches were tested. Across all biological materials, DNA was able to be recovered from the top side of all 60 swatches. For the underside, DNA was able to be recovered from 54 swatches. Of the 6 swatches that DNA was unable to be recovered from, one sample was from semen and the rest were from saliva. This study has demonstrated that DNA and components of interest in forensically relevant biological material can be recovered from the opposite side to where it was originally deposited, and that observing biological material and/or DNA on one side of fabric does not definitively indicate direct deposition on that side. • DNA can be recovered from fabric on the underside to which it was deposited. • Biological material was detected on the fabric underside by presumptive tests. • Detectability may differ between fabric and biological material type. • DNA may still be recovered in the absence of a positive presumptive test. [ABSTRACT FROM AUTHOR]

The inception of forensic DNA elimination database represents a pivotal advancement in forensic science, aiming to streamline the process of distinguishing between DNA found at crime scenes and that of individuals involved in the investigation process, such as law enforcement personnel and forensic lab staff. In subsequent phases, once familiarity with the database is achieved by its administrators and other stakeholders, and they have accrued sufficient experience, the possibility of expanding the database to encompass first responders—including firefighters, paramedics, emergency medical technicians, and other emergency services personnel—can be contemplated. Key challenges in managing these databases encompass the grounds for collecting samples, ensuring the integrity of both samples and profiles, along with the duration of retention, access to the database, and the protocols to follow when a match is found in the database. This paper outlines the conceptual and detailed legislative framework in Hungary, where the forensic DNA elimination database was introduced in 2022. • Elimination DNA databases help exclude individuals with legitimate reasons for being at a crime scene by compiling their DNA profiles. • The utilization of the elimination database was introduced in Hungary on January 1, 2022; however, a systematic analysis of the regulation suggests improvements to the regulation. [ABSTRACT FROM AUTHOR]

Awareness of the factors surrounding the transfer of DNA from a person, item, or surface to another person, item, or surface is highly relevant during investigations of alleged criminal activity. Animals in domestic environments could be a victim, offender, or innocent party associated with a crime. There is, however, very limited knowledge of human DNA transfer, persistence, prevalence, and recovery (DNA TPPR) associated with domestic animals. This pilot study aimed to improve our understanding of DNA TPPR associated with domestic dogs by collecting and analysing samples from various external areas of dogs of various breeds, interactions with humans, and living arrangements, and conducting a series of tests to investigate the possibility of dogs being vectors for the indirect transfer of human DNA. Reference DNA profiles from the dog owners and others living in the same residence were acquired to assist interpretation of the findings. The findings show that human DNA is prevalent on dogs, and in the majority of samples, two-person mixtures are present. Dogs were also found to be vectors for the transfer of human DNA, with DNA transferred from the dog to a gloved hand during patting and a sheet while walking.

The sensitivity and discrimination power of modern DNA profiling systems means that very small amounts of DNA from an individual can be detected on an item leading to large inclusionary statistics for that person. The sensitivity of these systems has significant benefits in the investigation of crime but also can be highly sensitive to contamination of exhibits or crime scenes. It becomes critical to distinguish between deposition during commission of a crime or deposition via some other method unrelated to the crime. This study investigates methodologies used in crime scene examination and the potential for them to cause non-crime-related transfer of DNA. Factors assessed include the source of DNA, the handling time, the amount of movement during contact, and the substrate type. The amount of movement and the number of transfer steps are the most critical in determining whether, and how much, DNA is transferred. This study provides information for crime scene examiners and also scientists assessing transfer scenarios. [ABSTRACT FROM AUTHOR]

Background: Saposhnikovia divaricata (Turcz.) Schischk. is a perennial herb whose dried roots are commonly used as a source of traditional medicines. To elucidate the organelle-genome-based phylogeny of Saposhnikovia species and the transfer of DNA between organelle genomes, we sequenced and characterised the mitochondrial genome (mitogenome) of S. divaricata. Results: The mitogenome of S. divaricata is a circular molecule of 293,897 bp. The nucleotide composition of the mitogenome is as follows: A, 27.73%; T, 27.03%; C, 22.39%; and G, 22.85. The entire gene content is 45.24%. A total of 31 protein-coding genes, 20 tRNAs and 4 rRNAs, including one pseudogene (rpl16), were annotated in the mitogenome. Phylogenetic analysis of the organelle genomes from S. divaricata and 10 related species produced congruent phylogenetic trees. Selection pressure analysis revealed that most of the mitochondrial genes of related species are highly conserved. Moreover, 2 and 46 RNA-editing sites were found in the chloroplast genome (cpgenome) and mitogenome protein-coding regions, respectively. Finally, a comparison of the cpgenome and the mitogenome assembled from the same dataset revealed 10 mitochondrial DNA fragments with sequences similar to those in the repeat regions of the cpgenome, suggesting that the repeat regions might be transferred into the mitogenome. Conclusions: In this study, we assembled and annotated the mitogenome of S. divaricata. This study provides valuable information on the taxonomic classification and molecular evolution of members of the family Apiaceae. [ABSTRACT FROM AUTHOR]

The technical advancements made in DNA profiling now allow for very low DNA amounts to be analyzed. Accordingly, the argument often made in criminal courts is not who the DNA belongs to but rather how it was deposited. Despite the complexity of the relevant DNA transfer, persistence, prevalence, and recovery issues, forensic laboratories in some European countries have used evaluative reports with activity level propositions, while this is not current practice in the United States. The purpose of this study was to gain an overview of the opinions about activity level reporting (ALR) held by forensic biologists in the United States. A seventeen‐question survey was distributed to members of the American Society of Crime Laboratory Directors and U.S. members of the International Society for Forensic Genetics. The survey included multiple‐choice and open‐response questions and received 54 responses. The majority of responses expressed moderate support of ALR. Participants mentioned six major concerns to be addressed prior to implementing ALR in the United States: (1) effect of number of variables involved; (2) need of education for practitioners/legal system; (3) inadequate number of activity studies with realistic scenarios; (4) difficulty of achieving admissibility in court; (5) need for standardized approaches/guidelines; and (6) requisite shift in perspective as to the validity of ALR. Overall, this small segment of U.S. forensic DNA practitioners appear to be willing to implement ALR once these concerns are fully addressed and resolved. As a follow‐up, it would be worthwhile exploring these and other questions with a larger group and also other disciplines. [ABSTRACT FROM AUTHOR]

Domestic animals, such as cats and dogs, are present in the majority of Australian households. Recently, questions regarding the possibility that domestic animals can serve as silent witnesses, from whom evidence can be collected, or act as vectors of contamination and transfer, have started to be raised. Yet, little is known regarding the transfer and prevalence of human DNA to and from cats. This study investigated if cats are reservoirs and vectors for human DNA transfer. Twenty cats from 15 households were sampled from 4 different areas (head (fur), back (fur), left (skin) and right (fur)) to obtain information on the background DNA that may be found on an animal. Further, transfer of human DNA to and from an animal, after a short patting contact, was tested. Human DNA was found to be prevalent on all cats. Of the areas sampled, most DNA was collected from the top of the fur from the back followed by the head and right/fur. No or very low quantities of human DNA was recovered from the left (skin) area. Most of the human DNA originated from the owners, but DNA from others was also often present (47 % of samples). Further, the transfer tests demonstrated that human DNA transferred readily to (detected in 45 % of samples) and from (detected in 80 % of samples) cats during patting. These results show that animals can act as reservoirs of human DNA and vectors for human DNA transfer that may need to be considered during evaluative DNA reporting. Furthermore, if an interaction between an animal and a perpetrator is suspected, consideration should be given to collecting DNA evidence from suspected contact areas on an animal., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The mitochondrial plastid DNAs (MTPTs) in seed plants were reported more than 40 years ago and exhibited a high diversity regarding gene content, quantity, and size. However, the mechanism that resulted in the current diversity of MTPTs in angiosperms has not been fully discovered. In this study, we sequenced and characterized the complete organelle genomes of Limonia acidissima L., a monotypic species of Rutaceae. The newly generated and previously published organelle genomes of 42 species were used to explore the diversity of MTPTs regarding quantity, gene content, size, and coverage of chloroplast genome (cpDNA) regions. The results showed that the number of MTPTs ranged from three to 74, of which the lengths were from 100 to 53,731 bp. The highest coverage of MTPTs was found in the inverted repeat region, whereas the small single repeat region had the lowest coverage. Based on the previous data and current results, we propose a scenario for the diversity of MTPTs in angiosperms. In the first stage, the whole cpDNA might migrate to the mitogenome. Then, different genomic events, such as duplication, deletion, substitution, and inversion, have occurred continuously and independently and resulted in extremely variable profiles of mitogenomes among angiosperms. Our hypothesis provides a new and possibly reliable scenario for explaining the present circumstances of MTPTs in angiosperms. However, more genomic data should be mined, and more studies should be conducted to clarify this natural phenomenon in plants., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

• The mitochondrial genome of Rhododendron delavayi was assembled. • Genes rearranged among the mitochondrial genomes of Rhododendron species. • Rhododendron species grouped together in the mitochondrial phylogenetic tree. • Plastid-to-mitochondrial genes transferred in R. delavayi. • Mitochondrial fragments transferred in R. delavayi. Rhododendron delavayi , a notable ornamental plant primarily found in regions of China like Yunnan and Guizhou provinces, holds substantial horticultural value. To elucidate the systematic phylogenetic relationships and organelle genomic differences within R. delavayi and related Rhododendron species, we conducted sequencing and assembly of the complete mitochondrial genome of R. delavayi. The full-length mitochondrial genome of it was a singular circular molecule spanning 1,009,263 bp, comprising 53 protein-coding genes, including 18 transfer RNA (tRNA) genes, 3 ribosomal RNA (rRNA) genes, and 32 protein-coding genes. A total of 1,182 simple sequence repeats (SSRs) loci were identified in the R. delavayi mitochondrial genome, primarily consisting of single nucleotide, dinucleotide, and trinucleotide repeats. Nucleotide diversity analysis highlighted five genes (atp6 , atp9 , cox2 , nad1 , and rpl10) with the highest diversity within the mitochondrial genomes of Rhododendron genus. Comparative analysis of the mitochondrial genome of R. delavayi with those of four other Rhododendron species indicated complex rearrangements in 21 genes, including rps4 , nad6 , rps3 , atp6 , cob , atp9 , nad7 , among others. The mitochondrial phylogenetic tree revealed a close relationship between R. delavayi and R. decorum , forming a sister clade to R. × pulchrum and R. simsii. Furthermore, 126 plastid-to-mitochondrial gene transfers in R. delavayi were identified, ranging from 30 bp to 19,385 bp. These fragments collectively constituted 47.54 % and 9.52 % of the chloroplast and mitochondrial genomes (202,169 bp), respectively. Complex mitochondrial-to-mitochondrial transfers were also observed, with 843 identified fragments totaling 312,036 bp (30.92 % of the mitochondrial genome). Segments exceeding 10 kb may mediate homologous recombination within the mitochondrial molecules. Remarkably, our study underscores that the mitochondrial genome of R. delavayi was the largest reported within the Rhododendron genus to date. The intricate rearrangements observed in the mitochondrial genomes of Rhododendron species, alone with the identification of five potential molecular marker sites, provided valuable insights for species classification and parentage identification within the Rhododendron genus. [ABSTRACT FROM AUTHOR]

The heightened sensitivity of DNA typing techniques, paired with the extensive use of trace DNA in forensic investigations, has resulted in an increased need to understand how and when DNA is deposited on surfaces of interest. This study focussed on the transfer, persistence, and prevalence of trace DNA in a single occupation of an office space by an intruder, when all contacts made during occupation and for the two hours prior and post occupation were known. The extent to which DNA could be recovered from contacted/not contacted surfaces was investigated. This study investigates the impacts of these movements and use of an office space when the duration of occupancy, surface contact histories and shedder status of participants are known. Contacts were documented and surfaces in the office space were targeted for sampling. Categories were set for target sampling that included different types of contact. Direct and indirect DNA transfer was detected in 55 % and 6 % of samples, respectively. Contactless DNA transfer was detected in 0.5 % of samples. The owner was observed as the sole/major/majority contributor in 77 % of the samples and as minor contributor in 10 % of samples. The intruder was observed as the sole/major/majority contributor in 14 % of samples and as the minor contributor in 16 %. An increased number of contacts increased the relative DNA contribution of the individual making the contact, however, not all observed direct contacts resulted in detectable DNA transfer. The outcome of this study will aid in better sample targeting strategies and contribute to the pool of data assisting in the development of activity level assessments. • Owner DNA was more prevalent than the intruder DNA. • Longer contacts and smaller surface items resulted in higher intruder detection. • Intruder was detectable even after subsequent contact of surface by owner. • Indirect and contactless transfer detected in 6 % and 0.5 % of samples respectively. • Increased number of contacts resulted in increased detection. [ABSTRACT FROM AUTHOR]

Considering activity level propositions in the evaluation of forensic biology findings is becoming more common place. There are increasing numbers of publications demonstrating different transfer mechanisms that can occur under a variety of circumstances. Some of these publications have shown the possibility of DNA transfer from site to site on an exhibit, for instance as a result of packaging and transport. If such a possibility exists, and the case circumstances are such that the area on an exhibit where DNA is present or absent is an observation that is an important diagnostic characteristic given the propositions, then site to site transfer should be taken into account during the evaluation of observations. In this work we demonstrate the ways in which site to site transfer can be built into Bayesian networks when carrying out activity level evaluations of forensic biology findings. We explore the effects of considering qualitative vs quantitative categorisation of DNA results. We also show the importance of taking into account multiple individual's DNA being transferred (such as unknown or wearer DNA), even if the main focus of the evaluation is the activity of one individual. • Site-to-site DNA transfer on an exhibit can be important to consider in an evaluation. • We show several methods of incorporating site-to-site transfer in a Bayesian network. • Modelling DNA amounts vs presence/absence has an effect on evaluation outcomes. • Modelling multiple people's DNA transfer within a trace effects evaluation outcome [ABSTRACT FROM AUTHOR]

According to the principle of Locard " Every contact leaves a trace ", when touching a surface, a bi-directional transfer of self and non-self-DNA residing on the hands and touched objects can occur. Metals are commonly encountered in forensic evidence and, during hand contact with these surfaces, a transfer of metal particles could occur together with the transfer of human DNA. This study proposes a proof-concept approach for the original detection of metal particles and touch DNA to track the activity performed by a donor and particularly to assess the metallic substrate touched before the contact with a subsequent surface. To this scope, a scenario of contact events was simulated by three volunteers, who participated in fingerprint deposition firstly on copper and then on plastic and glass surfaces. Twenty-four stubs were collected on the hands of volunteers and the secondary surfaces and then analyzed by environmental scanning electron microscopy (ESEM). DNA was quantified only from copper and plastic surfaces. Ten additional volunteers followed the same protocol of deposition on copper and then on plastic surfaces to evaluate DNA transfer only. On 20 touch DNA samples, the copper surface yielded significantly lower DNA amounts, ranging from 0.001 to 0.129 ng/μl, compared to the secondary touched plastic surface, ranging from 0.007 to 0.362 ng/μl. ESEM-EDS analysis showed that copper particles could be abundantly detected on the hands of the volunteers after contact with the copper surface. Particles containing silicates with copper were shown on plastic, while they were only found in 1/3 of samples on glass. Our proof-of-concept study has shown that ESEM-EDS analysis has the potential to detect copper particles transferred to the hands of volunteers during contact with a copper metallic surface and deposited on secondarily touched items. The results suggest that this original ESEM-DNA parallel approach could potentially allow the tracking of DNA transfer and metal particles at a crime scene, although this represents only a first step and further research on a wider casuistry could help to address the interpretation of results given activity level propositions. • The copper surface yielded significantly lower DNA amounts compared to plastic. • ESEM analysis can detect copper transferred from the hands to secondary surfaces. • A proof-of-concept ESEM-DNA approach to track the DNA transfer is presented. • The approach addresses interpretation of results given activity level propositions. [ABSTRACT FROM AUTHOR]

The sensitivity of DNA analysis has progressed to the point that trace levels of DNA, originating from only a few cells, can generate informative profiles. This means that virtually any item or surface can be sampled with a reasonable chance of obtaining a DNA profile. As the presence of DNA does not suggest how it was deposited, questions are often raised as to how the DNA came to be at a particular location and the activity that led to its deposition. Therefore, understanding different modes of DNA deposition, reflective of realistic forensic casework situations, is critical for proper evaluation of DNA results in court. This study aimed to follow the movements of DNA to and from individuals and common household surfaces in a residential premises, while socially interacting. This took place over an hour and involved four participants, with known shedder status, designated as visitors (a male and a female) and hosts (a male and a female), who engaged in the activity of playing a board game while being served food. During the study, the participants were instructed to use the toilet on a single occasion to assess the transfer of DNA to new and unused underwear that was provided. All contacts made by the participants in the dining room and kitchen were video recorded to follow the movements of DNA. Samples were collected based on the history of contact, which included hands, fingernails and penile swabs. Direct contacts resulted in detectable transfer (LR > 1) in 87 % (87/100) of the non-intimate samples and clothing. For surfaces touched by multiple participants, DNA from the person who made the last contact was not always detectable. The duration and number of contacts did not significantly affect the detection of the person contacting the item. On the other hand, presence of background DNA and participant's shedder status appear to play an important role. Further, unknown contributors were detected in the majority of samples. Finally, indirect transfer was observed on a number of occasions including co-habiting partners of guests who were not present at the study location. The results of this study may assist with decision making for exhibit selection or targeting areas for sampling within the home environment. Our findings can also be used in conjunction with previous literature to develop activity-level evaluations in such situations where the source of the DNA is conceded, but the mode of deposition is disputed. • Direct contact resulted in person detection in 66 % of the samples. • Indirect DNA transfer confirmed in 7 % of samples, usually as a minor contribution. • No significant impact of contact duration and number of contacts on DNA detection. • Background DNA appears to influence POI detection and can mask shedder effects. • Last contacts do not always result in detectable transfer of DNA. [ABSTRACT FROM AUTHOR]

Individuals leave behind traces of their DNA wherever they go. DNA can be transferred to surfaces and items upon touch, can be released into the air, and may be deposited in indoor dust. The mere presence of individuals in a location is sufficient to facilitate either direct or indirect DNA transfer into the surrounding environment. In this study, we analyzed samples recovered from commonly touched surfaces such as light switches and door handles in an office environment. We evaluated two different methods to isolate DNA and co-extract DNA and RNA from the samples. DNA profiles were compared to the references of the inhabitants of the different locations and were analyzed taking into consideration the type of sampled surface, sampling location and information about the activities in a room during the sampling day. Results from DNA samples collected from surfaces were also compared to those from air and dust samples collected in parallel from the same areas. We characterized the amount and composition of DNA found on various surfaces and showed that surface DNA sampling can be used to detect occupants of a location. The results also indicate that combining information from environmental samples collected from different DNA sources can improve our understanding of DNA transfer events in an indoor setting. This study further demonstrates the potential of human environmental DNA as an investigative tool in forensic genetics. • Characterization of DNA amount and composition on different surfaces. • Surface DNA sampling to identify occupants of a location. • Human eDNA from air, dust and surfaces as investigative tool. • DNA transfer from surfaces, dust and air in an indoor environment. • Extraction method affects DNA quality and quantity from touch deposits. [ABSTRACT FROM AUTHOR]

Increasingly in courts, the source of forensic DNA trace evidence is not challenged by the defence. Instead, the issue relates to how the suspect's DNA got to the crime scene, suggesting it arrived via a legitimate activity. Many burglaries are committed using a new lock-picking method called 'foil impressioning', which involves inserting aluminium foil into the lock. When DNA is recovered from this foil, suspects will say that they only cut the foil and sell or discard it, to be used later in lock-picking by someone else. This study elucidates the probabilities of recovering DNA profiles from aluminium foil in three situations: (1) when a person only cuts the foil, (2) when they cut and then use it for lock-picking and (3) when they cut it and someone else uses it for lock-picking. Using a Bayesian network, we conclude that the probability of recovering a person's DNA profile from foil inside a picked lock is seven times higher if they picked the lock than if they only cut the foil. This study demonstrates how likelihood ratios based on probabilistic models of DNA transfer and persistence can now help the court address questions about the mode of deposition of DNA traces. [ABSTRACT FROM AUTHOR]

Items from crime scenes are frequently packaged and transported to laboratories for forensic examination. The packaging primarily maintains the integrity of forensic evidence associated with the item by protecting it from contamination and environmental impacts, plus limiting and recording access. There is diversity in the types of packaging used. We are aware that DNA-containing material may transfer from an item to the internal side of packaging and/or from one area of an item to another area, potentially limiting generation of good quality DNA profiles and/or affecting their interpretation. However, the level of transfer risk is unclear, as are the main impacting factors. It is thus highly relevant to improve our understanding of these. Here we explore what commonly applied standards prescribe regarding packaging requirements to maintain the integrity of DNA on a packaged item, conduct further studies confirming the risk of transfer, and suggest packaging features requiring research considerations that may limit the risk of DNA transfer within packaging. [ABSTRACT FROM AUTHOR]

Knowledge of DNA-TPPR in various settings and circumstances can aid sample targeting and collection, interpretation of DNA profiles, and activity level assessments. The present study looks at a number of items/surfaces in a single-use office space that was sequentially used for one hour by the owner, a temporary occupant (intruder), and the owner (3 h total). Video recording allowed evaluation of contacts made by participants to assist targeted sampling. In a majority of samples, the owner of the office space was the major contributor regardless of the last person to have contacted an item/surface. The DNA of the intruder persisted after contact on 7 of 19 items/surfaces that the owner of the office space re-used. Interestingly, the participants picked up DNA from each other on hands and clothing via indirect transfer. [ABSTRACT FROM AUTHOR]

• DNA transfers without contact from used fabric items after gentle shaking. • DNA transfers at levels sufficient to produce informative profiles. • The profiles of the transferred DNA closely resemble that of the primary item. DNA is frequently retrieved from commonly used objects or surfaces with no apparent biological stains. This DNA may have come from one or more individuals who directly deposited their DNA, or indirectly transferred the DNA of others, when physically contacting the sampled object or surface. Furthermore, contactless indirect DNA transfer of this 'touch DNA' from fabric substrates was recently demonstrated to be possible in a controlled laboratory environment. The circumstances and extent to which this form of contactless DNA transfer occurs are largely unknown. This study investigated indirect DNA transfer without contact by applying a gentle shaking agitation to used clothing, pillowcases and towels, with known usage and history, of 10 volunteers above the collection zone of the secondary surface. DNA transfer frequently occurred and was possible from all three investigated items. It occurred at levels that often produced informative profiles where transferred profiles closely resembled the profiles generated from the primary item. The outcomes of this study contribute to expanding the understanding of indirect DNA transfer without contact. However, this field would benefit from investigating a wider range of agitations and/or item types with various histories of use to determine the level of transfer and its detectability under different conditions. [ABSTRACT FROM AUTHOR]

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Technological developments within the field of forensic genetics have enhanced the sensitivity and specificity of DNA testing tremendously and have broadened the applications of biological evidence in criminal investigations. Evaluation and communication of the evidential findings within criminal cases have not maintained the same pace, which has largely stemmed from a failure to adopt a standardized approach within and across the various fields of forensic science. Within forensic biology, this has led to unjustified opinions on the weight of the evidence and occurrences of the association fallacy, when the weight of evidence given propositions at one level of the hierarchy of propositions is inappropriately transposed to a higher level. We further define the association fallacy to include the terms, "source level fallacy" and "activity level fallacy," to enable the forensic science community to better identify and address issues in biological evidence evaluation. It is important to understand these concepts and their causes, and in doing so, identify potential avenues to avoid these fallacies in forensic science casework. These avenues include training and education of forensic and legal professionals, as well as research into transfer, persistence, prevalence and recovery (TPPR) of DNA and biological evidence in general. This article is categorized under:Forensic Biology > Interpretation of Biological Evidence [ABSTRACT FROM AUTHOR]

Over recent years, DNA profiling techniques have become highly sensitive. Even small amounts of DNA at crime scenes can be analysed leading to new defence strategies. At court, defence lawyers rarely question the existence of a DNA trace (source level) but challenge how the DNA was transferred to the scene (activity level). Nowadays, the most common defence strategy is to claim that somebody else had stolen the defendant's gloves and used them while breaking and entering. In this study we tested this statement. Using gloves made of different material (cloth, leather, rubber) and varying secondary transfer surfaces (wood, metal, glass), we simulated a few of the most likely transfer scenarios that occur during breaking and entering. While we detected the presence of DNA on the outside of 92 of the 98 gloves tested, we observed only one case of secondary transfer in a total of 81 transfer experiments. This data demonstrates that secondary transfer under conditions resembling realistic conditions is a very rare event. [ABSTRACT FROM AUTHOR]

Since the first shedder test was formulated almost 20 years ago, a plethora of different test strategies has emerged. The amount of data generated so far is considerable. However, because of the limited reproducibility of its results, the reliability of the shedder concept is frequently questioned. This study provides a literature overview of applied shedder tests that capture the diversity of the concept. It is pointed out to what extent different classification criteria, workflows, and trace evaluation can impair the classification outcome. The robustness of shedder status was assessed by applying a promising approach established by Fonneløp et al. (Forensic Sci Int Genet 29:48–60, 21). Data provide similar results to those in recent studies but also ambiguous shedder classifications. The applied shedder test was adapted based on our own as well as the reviewed data. With novel classification parameters, promising results were achieved. This study reveals uncertainties and inconsistencies of the shedder concept. Recommendations for harmonization and transparency are proposed. Implementation of the recommendations may result in an increased impact on casework and transfer studies, including activity-level assessments. Furthermore, this study shows that moisturizers affect participants' shedder status as well as DNA transfer. The impact appears to remain relevant even 60 min post ointment application but depends greatly on the type of moisturizer applied. [ABSTRACT FROM AUTHOR]