Reliability of phenotype estimation and extended classification of ancestry using decedent samples.

The Illumina® MiSeq FGx™, in conjunction with the ForenSeq™ DNA Signature Prep kit, produces genotypes of the CODIS-required short tandem repeats and provides phenotype and biogeographical ancestry estimations via phenotype-informative and ancestry-informative markers, respectively. Although both markers have been validated for use in forensic biology, there is little data to determine the practical utility of these estimations to assist in identifying missing persons using decedent casework samples. The accuracy and utility of phenotypic and ancestral estimations were investigated for 300 samples received by the Los Angeles County Department of Medical Examiner-Coroner. piSNP genotypes were translated into hair and eye colors using the Forenseq™ Universal Analysis Software (UAS) on the MiSeq FGx™ and the HIrisPlex System, and statistical accuracy was evaluated in context with the reported decedent characteristics. Similarly, estimates of each decedent's biogeographical ancestry were compared to assess the efficacy of these markers to predict ancestry correctly. The average UAS and the HIrisPlex system prediction accuracy for brown and blue eyes were 95.3% and 96.2%, respectively. Intermediate eye color could not be predicted with high accuracy using either system. Other than the black hair phenotype reporting an accuracy that exceeded 90% using either system, hair color was also too variable to be predicted with high accuracy. The FROG-kb database distinguishes decedents adequately beyond the Asian, African, European, and Admixed American global ancestries provided by the MiSeq FGx™ UAS PCA plots. FROG-kb correctly identified Middle Eastern, Pacific Islander, Latin American, or Jewish ancestries with accuracies of 70.0%, 81.8%, 73.8%, and 86.7%, respectively.

DNA methylation of decedent blood samples to estimate the chronological age of human remains.

Chronological age estimation may offer valuable investigative leads in human identification cases. Bisulfite pyrosequencing analysis of single CpG sites on five genes (KLF14, ELOVL2, C1orf132, TRIM59, and FHL2) was performed on 264 postmortem blood samples from individuals aged 3 months to 93 years. The goals were to develop age prediction models based on the correlation between the methylation profile and chronological age and to assess the accuracy of the prediction. Linear regression between methylation levels and age at each CpG site revealed that the five markers show a statistically significant correlation with age. The methylation data from a training set of 160 postmortem blood samples were used to develop an age prediction model with a correlation coefficient of 0.65, explaining 73.1% of age variation, with a mean absolute deviation from the chronological age of 7.60 years. The accuracy of the model was evaluated with a test set of 72 samples producing a mean absolute deviation of 7.42 years. The training and test sets were also categorized by specific age groups to assess accuracy and deviation from chronological age. The data for both sets revealed a lower prediction potential as an individual increases in age, particularly for the age categories above 50 years.

Identification of polygonal barrel rifling characteristics in bullet wipe residue deposited on textiles.

This study examines the potential formation of land and groove rifling characteristics in bullet wipe residue deposited on textile fabrics. Textile fabrics comprised of natural, synthetic, semi-synthetic, and blended fibers were damaged either individually or as triplicate layers using two different ammunition types: Winchester WinClean 115 grain 9 mm Luger BEB and Speer 115 grain 9 mm Luger TMJ. Each ammunition type was fired in triplicate using a 9 mm Luger caliber Glock 17 at a distance of approximately 6 feet at normal incidence to the target. The bullet hole was first observed under a stereomicroscope, photographed under tungsten and infrared illumination to observe chemical residues, and subsequently tested for the presence of copper and lead residues. The preliminary chemical results show that land and groove rifling class characteristics can form in bullet wipe residue deposited on textile fabrics. The composition of the fabric, cleanliness of the interior surface of the firearm barrel, presence of intervening layers of fabric, and the bullet type are all potential contributing factors to the detection of rifling characteristics.

Forensic intelligence applied to questioned document analysis: A model and its application against organized crime.

The capability of forensic sciences to fight crime, especially against organized criminal groups, becomes relevant in the recent economic downturn and the war on terrorism. In view of these societal challenges, the methods of combating crime should experience critical changes in order to improve the effectiveness and efficiency of the current resources available. It is obvious that authorities have serious difficulties combating criminal groups of transnational nature. These are characterized as well structured organizations with international connections, abundant financial resources and comprised of members with significant and diverse expertise. One common practice among organized criminal groups is the use of forged documents that allow for the commission of illegal cross-border activities. Law enforcement can target these movements to identify counterfeits and establish links between these groups. Information on document falsification can become relevant to generate forensic intelligence and to design new strategies against criminal activities of this nature and magnitude. This article discusses a methodology for improving the development of forensic intelligence in the discipline of questioned document analysis. More specifically, it focuses on document forgeries and falsification types used by criminal groups. It also describes the structure of international criminal organizations that use document counterfeits as means to conduct unlawful activities. The model presented is partially based on practical applications of the system that have resulted in satisfactory outcomes in our laboratory.

Methane emissions from US low production oil and natural gas well sites.

Eighty percent of US oil and natural gas (O&G) production sites are low production well sites, with average site-level production ≤15 barrels of oil equivalent per day and producing only 6% of the nation's O&G output in 2019. Here, we integrate national site-level O&G production data and previously reported site-level CH4 measurement data (n = 240) and find that low production well sites are a disproportionately large source of US O&G well site CH4 emissions, emitting more than 4 (95% confidence interval: 3-6) teragrams, 50% more than the total CH4 emissions from the Permian Basin, one of the world's largest O&G producing regions. We estimate low production well sites represent roughly half (37-75%) of all O&G well site CH4 emissions, and a production-normalized CH4 loss rate of more than 10%-a factor of 6-12 times higher than the mean CH4 loss rate of 1.5% for all O&G well sites in the US. Our work suggests that achieving significant reductions in O&G CH4 emissions will require mitigation of emissions from low production well sites.

Evaluation of latent fingermark color contrast as aging parameter under different environmental conditions: A preliminary study.

This research expands previous studies in which color contrast between ridges and furrows of powder-enhanced latent fingermarks was explored as a possible aging parameter. The main goal is to test the sensitivity of the technique across a predetermined set of factors. In this case, experiment factors have included two donors who deposited sebaceous- and eccrine-rich fingermarks onto ceramic tile and polystyrene plastic. These were developed with either black carbon or titanium dioxide powder (TiO2 ) over eight time periods (0-72 days) and aged under three light conditions (direct light, shade, and darkness). The mean intensity (MI) and intensity amplitude (IA) metrics of color were collected from each image for statistical analyses. Results show that color contrast is affected significantly by substrate, secretion, and powder types, with an interaction effect between the substrate and powder type on both MI and IA metrics. The degree of light exposure did not have a noticeable impact on distinguishing aging patterns of fingermarks by neither powder methods. Different aging patterns were detected between sebaceous-rich and their eccrine-rich counterparts for all light conditions using regression analysis. All eccrine-rich fingermarks exhibited little (or minimal) change in IA over time, whereas sebaceous-rich samples showed varied patterns, from significant decreases to slight increases. These findings confirm and expand previous observations on the potential use of MI and IA as metrics to study latent fingermark degradation patterns that could eventually be used to estimate the age of a fingermark.

Repeatability and reproducibility of the color contrast technique for fingermark age estimation applications.

This research complements previous studies in which color contrast between ridges and furrows of latent fingermarks was investigated as a potential aging parameter. In this case, the robustness of the technique has been tested by including five female and five male donors who deposited sebaceous-rich latent fingermarks onto ceramic tile and polystyrene plastic as well as flat and rolled inked fingerprints on commercially available ten-print cards. Fresh latent fingermarks were visualized with either carbon black or titanium dioxide powder (TiO2 ) and inked fingerprints were imprinted in succession without re-charging ink. The mean intensity (MI) and intensity amplitude (IA) metrics of the color histogram were collected from each image for statistical analyses. The goals were to detect any differences within and between the analysts' own interpretation of the protocol as well as examine how color contrast may be influenced by donor, substrate, biological sex, powder type, and the quantity of ink deposited. Results show that the color contrast metrics (MI and IA) are repeatable and reproducible and not affected significantly by donor, sex, deposition pressure, or distortion. However, the metrics were sufficiently sensitive to distinguish substrate and powder types and to detect different quantities of ink. The statistical analyses confirm and expand upon previous observations regarding the reliability of MI and IA as metrics that could eventually be used to estimate the age of a latent fingermark. At the same time, it was revealed that the technique needs further improvement and standardization by including a universal "white color standard" to conduct image comparisons.

Fingermark ridge drift: Influencing factors of a not-so-rare aging phenomenon.

Fingermark ridge drift is a random modification of (aged) fingermark patterns at a ridge scale. This phenomenon was previously proven to alter key elements used for identifications, such as the appearance of minutiae. Little is currently reported on the underlying factors contributing to its occurrence. The present study was designed to investigate further the variables of a previous study by including a total of 768 fingermarks from a male and female, two substrates (glazed ceramic tile and plastic), two distinct color powder developers (carbon black and titanium dioxide), three indoor lighting conditions (direct natural light, shade, and darkness), and two secretion types (sebaceous- and eccrine-rich). Fingermarks were aged for 2-72 days, powdered, photographed, and drift detected by three independent observers. All aged fingermarks (672) were compared relative to fresh fingermarks (96), and ridge drift was observed in 42 of 672 (6%) fingermarks, while 168 (25%) were reported as indeterminate results. While ridge drift was detected in multiple fingermarks across all independent variables, statistical analysis using a multinomial logistics model showed that only powder type, secretion type, and the substrate indicated a significant correlation with increased incidences of this phenomenon. There was no significant correlation with the donor, time since deposition, or the environmental lighting conditions used. The highest incidence occurred when carbon black powder was used on a plastic substrate (>10%). The average observation of ridge drift is 6% of samples supporting that this phenomenon is not a rare event, particularly considering the conservative analysis approach implemented.

The Capability of Raman Microspectroscopy to Differentiate Printing Inks.

This study applies Raman microspectroscopy to differentiate the chemical components in printing inks of different brands, colors, and type using the 532 nm and 785 nm excitation wavelengths. Spectra were collected from 319 inks (78 inkjet, 76 toner, 79 offset, and 86 intaglio) representing various colors. Comparisons were performed to calculate discrimination capability percentages for each ink type. Overall, Raman microspectroscopy differentiates according to the following hierarchy: intaglio (96%), inkjet (92%), offset (90%), and toner (61%). The ability of Raman microspectroscopy to differentiate between same-colored inks from different brands was dependent on the color and ink analyzed. Based on ink color, the discrimination capability ranged from 75 to 94% (inkjet), 0 to 86% (toner), and 0 to 77% (offset). Copper phthalocyanine was detected in cyan inks and various intaglio inks, while carbon black was identified in black inkjet, offset, and intaglio inks.

Ridge Width Correlations between Inked Prints and Powdered Latent Fingerprints.

A methodology to estimate the time of latent fingerprint deposition would be of great value to law enforcement and courts. It has been observed that ridge topography changes as latent prints age, including the widths of ridges that could be measured as a function of time. Crime suspects are commonly identified using fingerprint databases that contain reference inked tenprints (flat and rolled impressions). These can be of interest in aging studies as they provide baseline information relating to the original (nonaged) ridges' widths. In practice, the age of latent fingerprints could be estimated following a comparison process between the evidentiary aged print and the corresponding reference inked print. The present article explores possible correlations between inked and fresh latent fingerprints deposited on different substrates and visualized with TiO2 . The results indicate that the ridge width of flat inked prints is most similar to fresh latent fingerprints, and these should be used as the comparison standard for future aging studies.

Mitochondrial DNA amplification success rate as a function of hair morphology.

This study examines the amplification success rate of mitochondrial DNA from human head hair with respect to their potential for forensic application. Mitochondrial DNA was isolated using a Chelex-based extraction method and amplified using the LINEAR ARRAY duplex PCR system. The particular focus of this study was to characterize the morphological features of human head hair in order to further the understanding of the factors that influence amplification success rate in hair tissue using the LINEAR ARRAY duplex PCR system. 2554 head hairs from 132 individuals representing four population groups were amplified. The hair samples were characterized as follows: 1251 were identified microscopically as telogen hairs and 1303 were classified as hairs without roots (removed before extraction). Amplification success was assessed as a function of several independent variables: morphological characteristics; telogen root versus no root; donor age; scalp origin; use of cosmetic hair treatments; and race of the donor. The results show that a positive correlation exists between amplification success and the presence of a telogen root. Combining the amplification success with either the original or optimized protocol, telogen hairs result in an overall success rate of 77.5% compared with 65% for hairs with no roots. Controlling for telogen hairs, the findings indicate that the overall success rate is independent of cosmetic hair treatments; medulla structure; shaft length, diameter, and volume; and scalp origin. Conversely, the age of the donor, the race of the donor, and hair pigmentation all contribute to a variation in amplification success rate.

Variation in nuclear DNA concentrations during urination.

This study examined the cellular origin and concentration of nuclear DNA in human urine. Ten subjects provided two entire, first-morning voids: one as a single specimen and one as a consecutive series of samples. The serial samples were centrifuged, organically extracted, and quantified by slot-blot analysis. Total DNA concentrations ranged from 0.02 to 21.3 ng/mL for the males and 25.0 to 96.9 ng/mL for the females. The female samples were found to contain numerous vaginal epithelial cells. DNA was detected in all of the serial samples of nine subjects; however, the DNA concentrations varied considerably. With six subjects, the DNA concentration of the first serial sample was at least three times greater than that of the entire void. DNA was only detected in the first 21% of the void from one male subject. The results of this study have implications for the collection of urine samples.

Proximal End Root Morphology Characteristics in Antemortem Anagen Head Hairs.

The proximal end morphology of antemortem anagen head hair was compared with the characteristics documented to occur in postmortem hairs. Antemortem anagen and telogen head hairs (N = 967) were recovered following exposure to seven environments. Root morphology characteristics consistent with those reported in postmortem hairs were observed in 66 (14%) hairs exposed to a water, normal saline, outdoor soil, or indoor shower environment. Thirty-three anagen hairs (7%) exhibited a root band at the proximal end. The mean distance from the root tip to the onset of the root band ranged from 0.23 to 0.7 mm, depending on the environment. The mean distance from the root tip to the onset of the root band was 0.46 mm, with a mean band length of 0.44 mm. The results illustrate the need to better characterize postmortem banding through quantitative measurements, including the range for root tip to band distance and the overall band length.

Fingermark ridge drift.

Distortions of the fingermark topography are usually considered when comparing latent and exemplar fingerprints. These alterations are characterized as caused by an extrinsic action, which affects entire areas of the deposition and alters the overall flow of a series of contiguous ridges. Here we introduce a novel visual phenomenon that does not follow these principles, named fingermark ridge drift. An experiment was designed that included variables such as type of secretion (eccrine and sebaceous), substrate (glass and polystyrene), and degrees of exposure to natural light (darkness, shade, and direct light) indoors. Fingermarks were sequentially visualized with titanium dioxide powder, photographed and analyzed. The comparison between fresh and aged depositions revealed that under certain environmental conditions an individual ridge could randomly change its original position regardless of its unaltered adjacent ridges. The causes of the drift phenomenon are not well understood. We believe it is exclusively associated with intrinsic natural aging processes of latent fingermarks. This discovery will help explain the detection of certain dissimilarities at the minutiae/ridge level; determine more accurate "hits"; identify potentially erroneous corresponding points; and rethink identification protocols, especially the criteria of "no single minutiae discrepancy" for a positive identification.

STR-typing of human DNA from human fecal matter using the QIAGEN QIAamp stool mini kit.

The purpose of this study was to compare the effectiveness of the QIAGEN QIAamp Stool Mini Kit against a standard phenolchloroform procedure for the extraction, quantitation, and STR-typing of human nuclear DNA from human feces. Stools from six subjects were sampled by swabbing and excision. Samples extracted with the QIAamp kit gave a wide range of DNA yields, whereas those extracted by the organic method yielded no DNA. DNA was not recovered from one subject's stools by either procedure. The QIAamp extracts were amplified with the Profiler Plus and COfiler kits, and PCR inhibition was observed with DNA extracts that were further concentrated. Substitution of water or TE-4 for the QIAamp elution buffer eliminated most, if not all, of the inhibition. A modified QIAamp procedure was used to extract thirty samples, which were subjected to one of five environmental conditions. DNA was recovered from all of these samples, and typing results were obtained on 93% of the samples.

Effects of metformin on early pregnancy loss in the polycystic ovary syndrome.

Polycystic ovary syndrome is the most common form of female infertility in the United States. In addition to poor conception rates, pregnancy loss rates are high (30-50%) during the first trimester. We hypothesized that hyperinsulinemic insulin resistance contributes to early pregnancy loss in the syndrome, and that decreasing hyperinsulinemic insulin resistance with metformin during pregnancy would reduce the rate of early pregnancy loss. We conducted a retrospective study of all women with polycystic ovary syndrome who were seen in an academic endocrinology clinic within the past 4.5 yr and who became pregnant during that time. Sixty-five women received metformin during pregnancy (metformin group) and 31women did not (control group). The early pregnancy loss rate in the metformin group was 8.8% (6 of 68 pregnancies), as compared with 41.9% (13 of 31 pregnancies) in the control group (P < 0.001). In the subset of women in each group with a prior history of miscarriage, the early pregnancy loss rate was 11.1% (4 of 36 pregnancies) in the metformin group, as compared with 58.3% (7 of 12 pregnancies) in the control group (P = 0.002). Metformin administration during pregnancy reduces first-trimester pregnancy loss in women with the polycystic ovary syndrome.

A comparison of the effectiveness of swabbing and flossing as a means of recovering spermatozoa from the oral cavity.

This study examined whether flossing the teeth is a more effective collection method in recovering spermatozoa than conventional swabbing techniques. It was hypothesized that inclusion of flossing as a collection method would extend the recovery of spermatozoa to longer postcoital intervals (PCIs). Eighteen individuals provided 174 oral cavity samples. Successful recovery of spermatozoa was assessed with respect to the collection method and reported activity in the oral cavity during the PCI. Samples were subjected to a differential extraction procedure prior to microscopic evaluation of the extracted pellet. The results indicate that swabbing is more effective than flossing when the PCI falls within 1.5-12 h. However, spermatozoa were recovered from seven floss samples where the corresponding swabs gave negative results. When combining the results from the two collection methods, the percentage of subjects from whom spermatozoa are recovered increases for each PCI beyond the 0-h interval.

STR melting curve analysis as a genetic screening tool for crime scene samples.

In this proof-of-concept study, high-resolution melt curve (HRMC) analysis was investigated as a postquantification screening tool to discriminate human CSF1PO and THO1 genotypes amplified with mini-STR primers in the presence of SYBR Green or LCGreen Plus dyes. A total of 12 CSF1PO and 11 HUMTHO1 genotypes were analyzed on the LightScanner HR96 and LS-32 systems and were correctly differentiated based upon their respective melt profiles. Short STR amplicon melt curves were affected by repeat number, and single-source and mixed DNA samples were additionally differentiated by the formation of heteroduplexes. Melting curves were shown to be unique and reproducible from DNA quantities ranging from 20 to 0.4 ng and distinguished identical from nonidentical genotypes from DNA derived from different biological fluids and compromised samples. Thus, a method is described which can assess both the quantity and the possible probative value of samples without full genotyping.

Characterization of mitochondrial DNA sequence heteroplasmy in blood tissue and hair as a function of hair morphology.

This study characterizes mitochondrial DNA (mtDNA) sequence heteroplasmy in blood tissue and hair as a function of hair morphology. Bloodstains (127 individuals) and head hairs (128 individuals) were typed using the mtDNA LINEAR ARRAY™ assay. A total of 1589 hairs were interpreted: 1478 (93%) were homoplasmic and 111 (7%) exhibited heteroplasmy at one or more positions. Seventy-one percent (82/116) of individuals were homoplasmic, whereas 29% (34/116) exhibited heteroplasmy in at least one hair. The results demonstrate intra- and inter-tissue differences in heteroplasmy within individuals. Sequence heteroplasmy among hairs from each individual varied from 0 to 90%; the frequency does not differ significantly with population group, cosmetic treatment, age, gender, medulla morphology, region of the scalp, hair growth phase, or, when comparing living and deceased donors. However, the results support a correlation between heteroplasmy and hair pigmentation; typically, lighter-pigmented hairs exhibit a higher incidence of sequence heteroplasmy compared to darker hairs.