In 2018, the Oregon State Medical Examiner’s Office (OSME) received a grant from the Bureau of Justice Assistance to use investigative genetic genealogy (IGG) with Parabon NanoLabs (Parabon) to attempt to make identifications in their unidentified human remains cases. Samples were screened for DNA quantity and quality, and selected samples were sent for genome-wide single nucleotide polymorphism (SNP) generation. This multi-year collaboration has been extraordinarily successful: of 43 cases submitted, 39 cases have been investigated using IGG, and 30 have resulted in an identification so far.
Frequency estimation for Y-STR haplotypes is a challenging problem because limited data are available and complex dependencies exist within the data. As a result, various statistical methods have been proposed for frequency estimation. The discrete Laplace method has been recommended in some contexts by the DNA commission of the ISFG. This method is limited to haplotypes with single integer repeat alleles only at all loci. We propose a generalisation of the method that handles duplicated loci such as DYS385 and less common alleles that are not integer repeats. The extension is implemented in an experimental R package called disclapmix2.
SE33 was a well-known autosomal short tandem repeat (STR) marker that was high polymorphic and therefore was high discrimination power. The sequence structure of STR markers has been increasingly explored with nextgeneration sequencing (NGS) technology. The sequencing resulted in the development of a new locus designation and allele nomenclature that was also backward compatible with the conventional capillary electrophoresis. SE33 was one of the STR markers that had been coamplified by ForenseqTM Signature Prep Kit (Verogen) but were not analyzed and illustrated in the Universal Analysis Software (UAS) (Verogen). This study reported an ambiguous sequence-based allele 16.3 of the SE33 locus. This allele was observed while analyzed by STRait Razor 3.0. The configuration file was modified from the previous studies to include 15 bp of 5 & PRIME; flanking region and 24 bp of 3 & PRIME; flanking region. The ambiguous allele was called 16.3 (106 bp) with a read count of 2070. However, the sequence of the repeat region cannot be designated as allele 16.3. Several possible scenarios for allele designation were presented and discussed.
Cannabis plants have been cultivated around the world for thousands of years and are widely used in the textile industry and medicine. From the point of view of analyses for the needs of the justice system, they can be divided into two categories - hemp of the fibrous type and the narcotic type, which differ in the content of the psy-choactive compound THC. According to the guidelines, varieties with a content of active compounds above 0.2 % are considered to be the narcotic type. The standard approach used to distinguish between these two types of Cannabis is commonly used toxicological analysis. However, if the content of differentiating active compounds or the type of plant part sent to the laboratory is problematic, genetic identification may be a good solution. The subject of the study of the research consortium was the genetic analysis of Cannabis samples using STR markers. The collected population database of samples of Cannabis from fibrous and narcotic varieties was analyzed taking into account the basic statistical parameters describing the population. It was used to develop a method of genetic profiling of Cannabis on the basis of a selected set of 23 STR genetic markers, which were subjected to preliminary statistical analyses. The developed genetic models will be used to select the most useful genetic markers for the genetic identification of Cannabis and will enable the creation of an identification tool for forensic experts.
The evaluation of forensic DNA expert opinions (in some countries expert witness testimonies) and the way it affects criminal judgement is of paramount importance. We have selected one of the largest challenges when it comes to the evaluation of forensic DNA evidence, contamination of DNA samples, and examined how it influences the decisions judges make about the credibility of DNA evidence in Hungary.
