Back to Amido Black: Uncovering touch DNA in blood-contaminated fingermarks.

Blood-contaminated fingermarks (FMs) found in violent crime scenes may directly connect the suspect to the crime by linking the FM to the suspect and the DNA from the blood to the victim. However, marks that are incomparable are considered "dead-evidence" as the link to the suspect is lost. In this study, a novel approach was attempted to uncover the trace amount of touch DNA of the suspect in such marks. We examined the effect of two enhancement methods, ninhydrin (NIN) and amido black (AB), on DNA recovery from blood-contaminated FMs. A total of 108 fingerprints were deposited in three sets of depleted blood prints, blood-contaminated FMs, and latent FMs. All FMs were developed by either NIN or AB, or left undeveloped as reference followed by the quantification of the total DNA amount. This work shows that while AB had a detrimental effect on the quantity of blood-derived DNA specifically, reducing it by half, no similar effect was observed for touch DNA in latent FMs. This reduction led to the alteration of the major-to-minor DNA profile ratio to 70:30, thus enabling to obtain two distinct DNA profiles of the suspect from the touch DNA as well as the victim's profile from the blood. From an operational perspective, the use of AB in crime scenes may have an added value to retrieve the crucial DNA profile of the suspect, thus resurrecting a "dead-evidence."

An efficient and eco-friendly workflow for dual fingermark processing and STR profiling.

Since its discovery in 1997, DNA retrieved from touched or handled items (touch DNA) has been increasingly used in criminal casework. Depending on the nature of the substrate examined, numerous techniques are being used for fingermark (FM) collection and development, however, it has been shown that FM processing may impede or even prevent the dual analysis of FMs and DNA. In search for a possible solution, we have recently established a novel workflow for a non-destructive collection and eco-friendly visualization of latent FMs using white BVDA gel-lifters and black Wetwop® solution. In the present study, the scope and limitations of the proposed protocol were thoroughly examined for DNA recovery and genotyping in relation to substrate type (porous and non-porous), time elapsed after the deposition (1, 7 and 14 days) and donor's gender. The study included 120 developed FMs of 20 donors (10 males and 10 females, aged 25-50 years), from which 240 DNA samples were recovered and quantified. The independent analysis of two DNA samples recovered from each FM, one - from the adhesive surface of the gel-lifter and the other - from its imprint on the protecting acetate cover, allowed us not only to increase the total number of the identified donors, but also to achieve a higher level of confidence per FM. Though this approach appeared to be more efficient on non-porous substrates (up to 65% on car tin), it is noteworthy that forensically useful DNA profiles (with at least 8 full STR loci) were generated from poor-quality FMs on the porous substrate, drywall (25% and 15% in males and females, respectively). Finally, the integration of the results of touch DNA analysis and that of FM visual inspection allowed us to increase by more than half the number of personal identifications and to strengthen the chain of forensic evidence.

The Genomic History of the Bronze Age Southern Levant.

We report genome-wide DNA data for 73 individuals from five archaeological sites across the Bronze and Iron Ages Southern Levant. These individuals, who share the "Canaanite" material culture, can be modeled as descending from two sources: (1) earlier local Neolithic populations and (2) populations related to the Chalcolithic Zagros or the Bronze Age Caucasus. The non-local contribution increased over time, as evinced by three outliers who can be modeled as descendants of recent migrants. We show evidence that different "Canaanite" groups genetically resemble each other more than other populations. We find that Levant-related modern populations typically have substantial ancestry coming from populations related to the Chalcolithic Zagros and the Bronze Age Southern Levant. These groups also harbor ancestry from sources we cannot fully model with the available data, highlighting the critical role of post-Bronze-Age migrations into the region over the past 3,000 years.

Differential DNA methylation of vocal and facial anatomy genes in modern humans.

Changes in potential regulatory elements are thought to be key drivers of phenotypic divergence. However, identifying changes to regulatory elements that underlie human-specific traits has proven very challenging. Here, we use 63 reconstructed and experimentally measured DNA methylation maps of ancient and present-day humans, as well as of six chimpanzees, to detect differentially methylated regions that likely emerged in modern humans after the split from Neanderthals and Denisovans. We show that genes associated with face and vocal tract anatomy went through particularly extensive methylation changes. Specifically, we identify widespread hypermethylation in a network of face- and voice-associated genes (SOX9, ACAN, COL2A1, NFIX and XYLT1). We propose that these repression patterns appeared after the split from Neanderthals and Denisovans, and that they might have played a key role in shaping the modern human face and vocal tract.

DNA analysis of a 30,000-year-old Urocitellus glacialis from northeastern Siberia reveals phylogenetic relationships between ancient and present-day arctic ground squirrels.

In contrast to the abundant fossil record of arctic ground squirrels, Urocitellus parryii, from eastern Beringia, only a limited number of fossils is known from its western part. In 1946, unnamed GULAG prisoners discovered a nest with three mummified carcasses of arctic ground squirrels in the permafrost sediments of the El'ga river, Yakutia, Russia, that were later attributed to a new species, Citellus (Urocitellus) glacialis Vinogr. To verify this assignment and to explore phylogenetic relationships between ancient and present-day arctic ground squirrels, we performed 14C dating and ancient DNA analyses of one of the El'ga mummies and four contemporaneous fossils from Duvanny Yar, northeastern Yakutia. Phylogenetic reconstructions, based on complete cytochrome b gene sequences of five Late Pleistocene arctic ground squirrels and those of modern U. parryii from 21 locations across western Beringia, provided no support for earlier proposals that ancient arctic ground squirrels from Siberia constitute a distinct species. In fact, we observed genetic continuity of the glacialis mitochondrial DNA lineage in modern U. parryii of the Kamchatka peninsula. When viewed in a broader geographic perspective, our findings provide new insights into the genetic history of U. parryii in Late Pleistocene Beringia.

Comparison of common hard tissue cephalometric measurements between computed tomography 3D reconstruction and conventional 2D cephalometric images.

OBJECTIVE: To compare cephalostat two-dimensional (2D) measurements to 3D computed tomography (CT) measurements in order to determine the compatibility of CT landmarks identification for orthodontic purposes. MATERIALS AND METHODS: Ten human skulls were x-rayed in conventional lateral cephalogram and then scanned with spiral CT. Twenty-eight linear and angular cephalometric measurements were registered on the 2D lateral cephalogram and compared to the same measurement on the 3D CT scan. Significance of the results was determined by t-test for paired differences (P < .05). RESULTS: No difference was found between 2D and 3D images for linear or ratio measurements. As for the angular cephalometric measurements, only the sella turcica dependent measurements, showed significant difference between 2D and 3D. CONCLUSIONS: The compatibility of using most of the common orthodontic examined cephalometric measurements on 3D volume rendered image was proven except for the angular measurements that included sella anatomic landmark.

Y chromosome evidence for a founder effect in Ashkenazi Jews.

Recent genetic studies, based on Y chromosome polymorphic markers, showed that Ashkenazi Jews are more closely related to other Jewish and Middle Eastern groups than to their host populations in Europe. However, Ashkenazim have an elevated frequency of R-M17, the dominant Y chromosome haplogroup in Eastern Europeans, suggesting possible gene flow. In the present study of 495 Y chromosomes of Ashkenazim, 57 (11.5%) were found to belong to R-M17. Detailed analyses of haplotype structure, diversity and geographic distribution suggest a founder effect for this haplogroup, introduced at an early stage into the evolving Ashkenazi community in Europe. R-M17 chromosomes in Ashkenazim may represent vestiges of the mysterious Khazars.