Advances in forensic DNA quantification: A review

Abstract

This review focuses upon a critical step in forensic biology: detection and quantification of human DNA from biological samples. Determination of the quantity and quality of human DNA extracted from biological evidence is important for several reasons. Firstly, depending on the source and extraction method, the quality (purity and length), and quantity of the resultant DNA extract can vary greatly. This affects the downstream method as the quantity of input DNA and its relative length can determine which genotyping procedure to use-standard short-tandem repeat (STR) typing, mini-STR typing or mitochondrial DNA sequencing. Secondly, because it is important in forensic analysis to preserve as much of the evidence as possible for retesting, it is important to determine the total DNA amount available prior to utilizing any destructive analytical method. Lastly, results from initial quantitative and qualitative evaluations permit a more informed interpretation of downstream analytical results. Newer quantitative techniques involving real-time PCR can reveal the presence of degraded DNA and PCR inhibitors, that provide potential reasons for poor genotyping results and may indicate methods to use for downstream typing success. In general, the more information available, the easier it is to interpret and process the sample resulting in a higher likelihood of successful DNA typing. The history of the development of quantitative methods has involved two main goals-improving precision of the analysis and increasing the information content of the result. This review covers advances in forensic DNA quantification methods and recent developments in RNA quantification.

A new fast real‐time PCR method for the identification of three sibling Apodemus species (A. sylvaticus, A. flavicollis, and A. alpicola) in Italy

“…Real-time PCR is characterized by a much higher sensitivity compared to conventional PCR, being able to detect even very low copies of DNA (Angelone-Alasaad et al, 2015). For this reason, this modern method is now commonly used to amplify small or degraded samples (Holt et al, 2016;Lee, McCord, & Buel, 2014) or for diagnostic purposes (Caraguel, Stryhn, Gagne′, Dohoo, & Hammell, 2011). Although we only tested our method on fresh or well-preserved samples, given its sensitivity, it is likely to work on degraded (e.g., museum specimen) or low-DNA samples obtained through noninvasive sampling, such as feces and hair (e.g., obtained through hair-tubes; Kanthaswamy, Premasuthan, Ng, Satkoski, & Goyal, 2012).…”

Estimation de l’âge médicolégal grâce à l’étude de la méthylation de l’ADN : revue de la littérature

“…Le pyroséquençage est de loin la méthode ciblée la plus populaire pour l'analyse épigénétique médicolégale, non seulement en raison de sa simplicité, de sa facilité d'utilisation et de sa disponibilité pour les laboratoires médicolégaux, mais également en raison de sa résolution à l'échelle d'un CpG, de sa nature hautement quantitative et de sa sensibilité [32].…”

Cuantificación en tiempo real de un conjunto de muestras colombianas de relevancia histórica basado en la detección de un fragmento corto de la región hipervariable II del ADN mitocondrial

“…Las técnicas asociadas a la detección espectrofotométrica y al uso de geles de agarosa son relativamente económicas y de ejecución sencilla, sin embargo, sus limitaciones para detectar material genético escaso o agentes contaminantes que interfieren con la interpretación de los resultados son evidentes; en este sentido, las técnicas asociadas a la PCR son mucho más sensibles y específicas (24,25). dependen de la detección de sondas marcadas con flúor requieren de una inversión adicional, lo cual eleva los costos de la investigación.…”