Novel Y-chromosome short tandem repeat sequence variation for loci DYS710, DYS518, DYS385, DYS644, DYS612, DYS626, DYS504, DYS481, DYS447 and DYS449.

In forensic casework, Y-chromosome short tandem repeats (Y-STRs) are essential for differentiating between unrelated males and resolving the male component of admixed biological evidence. While the majority of Y-STRs are adequate for discriminating between different paternal lineages, rapidly mutating Y-STRs are necessary for improving discrimination between males within populations of low Y-chromosome diversity and between paternal relatives. Alternatively, sequencing of Y-STRs may also improve the discrimination between isometric Y-STR alleles by identifying variation in the repeat unit pattern arrangements and by identifying SNPs in the flanking region or within the STR repeat unit itself. In this report, a total of 153 DNA sequences are presented across the Y-STR loci DYS710, DYS518, DYS385, DYS644, DYS612, DYS626, DYS504, DYS481, DYS447 and DYS449. A total of 94 Y-STR sequences provided herein are reported for the first time, of which 37 sequences represent alleles showing size homoplasy, 34 sequences of known alleles for which sequence data has been unavailable and a total of 23 novel allele sequences across loci DYS644, DS447, DYS710 and DYS504. This study further encountered a rare sequence variant in the 5' flanking region of DYS385 and a total of two SNPs in the repeat structure at DYS481 and DYS449.

A novel FTA™ elute card collection method that improves direct DNA amplification from bloodstained concrete.

Concrete is a common construction material found in residential and commercial buildings, bridges and parking lots that is a composite matrix containing aggregate held together with cement. The porous nature of concrete can make the collection and genotyping of biological fluids, such as blood, challenging. Forensic evidence can become embedded within the matrix, potentially reducing the amount of DNA available for analysis. In forensic science, "direct" amplification refers to a genotyping method that amplifies a DNA profile directly from a sample without DNA extraction, saving time and money. We investigated a novel application of Whatman™ FTA™ Elute cards in their ability to directly amplify PowerPlex® Fusion and Y23 profiles from minute amounts of blood that had been deposited on different concrete structures. In comparison to traditional collection methods, directly profiling blood stained construction materials using FTA™ Elute cards increased the percentage loci amplified and significantly improved both allele peak height and peak height ratio while reducing allelic drop-out. FTA™ Elute cards can provide a reliable, inexpensive and superior alternative to traditional methods.

A potential new diagnostic tool to aid DNA analysis from heat compromised bone using colorimetry: A preliminary study.

Extracting viable DNA from many forensic sample types can be very challenging, as environmental conditions may be far from optimal with regard to DNA preservation. Consequently, skeletal tissue can often be an invaluable source of DNA. The bone matrix provides a hardened material that encapsulates DNA, acting as a barrier to environmental insults that would otherwise be detrimental to its integrity. However, like all forensic samples, DNA in bone can still become degraded in extreme conditions, such as intense heat. Extracting DNA from bone can be laborious and time-consuming. Thus, a lot of time and money can be wasted processing samples that do not ultimately yield viable DNA. We describe the use of colorimetry as a novel diagnostic tool that can assist DNA analysis from heat-treated bone. This study focuses on characterizing changes in the material and physical properties of heated bone, and their correlation with digitally measured color variation. The results demonstrate that the color of bone, which serves as an indicator of the chemical processes that have occurred, can be correlated with the success or failure of subsequent DNA amplification.

DNA analysis of skeletal tissue recovered from the English Channel.

This case study reports on DNA analysis from different skeletal elements of an individual recovered 2 years after going missing in the English Channel. Selected bones were also re-submerged for an additional 2 years and re-analysed. By comparing results from both time points, this study concludes that high-load-bearing bones, particularly the bones of the feet, appear to be a preferable source of DNA for identification of skeletal tissue recovered from similar conditions.

FTIR spectroscopy: A new diagnostic tool to aid DNA analysis from heated bone.

Deoxyribonucleic acid (DNA) extracted from skeletal tissue can be invaluable in genetic profiling applications, as it is often the only source available. Like all forensic samples, skeletal tissue may have been exposed to a variety of environmental insults, including heat. This study has focussed upon characterising changes in the material properties of bone that has been compromised by controlled heat treatments. These changes were then examined in relation to the subsequent success or failure of nuclear DNA (nDNA) amplification, using a range of differently sized amplicons, relevant to alternate profiling strategies. The results presented demonstrate that the ability to amplify nDNA correlates well with particular changes in mineral and organic content of bone. As such, we propose the application of a 'diagnostic triage tool' that can be performed quickly and at low cost on individual bone samples, in order to determine whether nDNA analysis is likely to be a viable option.