STRs vs. SNPs: thoughts on the future of forensic DNA testing

Abstract

Largely due to technological progress coming from the Human Genome and International HapMap Projects, the issue has been raised in recent years within the forensic DNA typing community of the potential for single nucleotide polymorphism (SNP) markers as possible replacements of the currently used short tandem repeat (STR) loci. Our human identity testing project team at the U.S. National Institute of Standards and Technology (NIST) has explored numerous SNP and STR loci and assays as well as developing miniSTRs for degraded DNA samples. Based on their power of discrimination, use in deciphering mixture components, and ability to be combined in multiplex assays in order to recover information from low amounts of biological material, we believe that STRs rather than SNPs will fulfill the dominant role in human identity testing for the foreseeable future. However, SNPs may play a useful role in specialized applications such as mitochondrial DNA (mtDNA) testing, Y-SNPs as lineage markers, ancestry informative markers (AIMs), the prediction of phenotypic traits, and other potential niche forensic casework applications.

Forensic DNA Technological Advancements as an Emerging Perspective on Medico-Legal Autopsy: A Mini Review

“…As a result of variance in the error rate of existing MPS assays, platforms and computational techniques, forensic validation of the quality of a NGS provided data is recommended [106]. With the application of MPS technology in the forensic genetic field, the limited number of STR and SNP capable of being [108] can be ignored, while increasing the potent application of SNPs in degraded samples, allowing the simultaneous analysis of different marker types and improving the high throughput for mitochondrial DNA testing as well in caseworking and databasing for laboratories [109]. Additionally, the implementation of MPS on the field of molecular autopsy can increase the genomic and etiological background in cases of sudden death, allowing for new therapies and strategies for treatment or prevention [110].…”

Revisión sobre los marcadores del origen biogeográfico y su aplicación en la investigación forense

“…Tienen un limitado número de variantes posibles por locus, de forma que si existe una variante representativa de la población, es más probable que la porte un gran porcentaje de los individuos de ese grupo. Además, la posibilidad de poder emplear pequeños amplicones favorece su genotipado mediante sistemas múltiplex e incrementa la posibilidad de éxito con muestras degradadas [12]. Por todo ello, el genotipado de snp autosómicos ha sido considerado como la herramienta ideal para la predicción del origen biogeográfico [13].…”

Scope of X-Chromosomal MiniSTRs: Current Developments

“…These 'minis' can prove essential where other anthropological methods cannot be applied for sex typing, phylogenies [87] and to explore the gender differences in the past populations [88,89]. Although SNPs are potential candidates for use with degraded samples, problems like low polymorphism and difficulty in mixture interpretation hinders their widespread use, outside the research setting [90].…”