Forensic analysis

This special issue of Electrophoresis is devoted to forensic analysis, and the focus of the issue is the adoption and adaptation of new technology and novel applications. Advances in the forensic field are nowhere more evident than in the continuing development of DNA typing methods. In this issue there are novel advances in methods and applications for DNA quantification, body fluid identification, single nucleotide polymorphisms, Y STRs and next generation sequencing. It is fascinating to see how far we have come when one considers that all forensic biological methods originated with the use of simple agarose electrophoretic gels and silver staining. These new applications include rapid multiplexed PCR, multi-wavelength capillary electrophoresis, and massively parallel sequencing. But these new advances are not just limited to forensic DNA typing. In this issue we also see interesting applications of mass spectrometry, fluorescence and conductivity detection in toxicological investigation and trace analysis. Many years ago a research committee mentioned to me that they thought the investment of time devoted to forensic applications in analytical chemistry would surely bear fruit in terms of interesting problems and research topics. Based on the depth and breadth of topics in this issue I think that that statement is even truer today. This new issue consists of 20 contributed research papers on forensic analysis divided into 6 general subtopics: DNA quantification and extraction, body fluid identification, DNA typing using short tandem repeats, massively parallel sequencing, toxicology and drug detection, and lastly sample characterization. The first set of papers describes important processes in DNA sample preparation. Here we see an article by Ginart et al. describing a method combining high resolution melt techniques in combination with real time PCR for autosomal and male DNA quantitation [1]. The next paper by Kulstein et al. discusses the interesting problem of simultaneously recovering RNA for body fluid identification and DNA for human identity. This can be important in instances when sample quantities are limited and multiple assays are required [2]. The next set of papers continues the discussion of body fluid identification. The first paper in this group by Antunes et al. provides information on the discovery of a new marker for the identity of vaginal epithelial cells. Such markers are useful in cases of sexual assault and child abuse [3]. There is also an interesting paper by Lee and co-workers, which is perhaps the first round robin study of methylation based body fluid identification. It involves laboratories in Europe, Asia, and America and utilizes a SNaPshot assay along with bisulfite modified PCR for sample identification [4]. The other two papers use various sequencing methods to explore the genome for additional markers for body fluid identification. A paper by Vidaki et al. utilizes pyrosequencing to explore previously identified CPG sites to detect the potential for tissue specific methylation. Two loci specific for semen were identified [5]. The last paper in this group by Seashols-Williams et al. utilized small RNAs isolated from a group of donors who provided sets of forensically relevant body fluids. Next generation sequencing was then used to compare results among the different cell types and determine specificity of the RNAs [6]. The third set of papers involves DNA typing using short tandem repeats. A variety of methods and applications were described. The first paper in this group by Yang et al. relates the development of a new rapid 21 locus STR multiplex which can be amplified from FTA and other substrates in under 90 minutes with no need for extraction [7]. The next paper by Liu et al. discusses methods for assessing kinship with STRs. A number of interesting case studies are provided [8]. The third paper in this group is by Moreno et al. and demonstrates a way to assess extraction efficiency and the effect of inhibition in STR typing by using DART based mass spectrometry [9]. The paper reveals how different robotic methods of sample preparation can affect sample cleanup. The last paper in this set by Abuidrees et al. demonstrates a rapid 30 min amplification of a Y chromosome based STR multiplex. Such a system can be important