The use of genetic markers, specifically Short Tandem Repeats (STRs), has been a valuable tool for identifying persons of interest. However, the ability to analyze additional markers including Single Nucleotide Polymorphisms (SNPs) and Insertion/Deletion (INDELs) polymorphisms allows laboratories to explore other investigative leads. INDELs were chosen in this study because large panels can be differentiated by size, allowing them to be genotyped by capillary electrophoresis.
View Article and Find Full Text PDFDNA analysis of forensic case samples relies on short tandem repeats (STRs), a key component of the combined DNA index system (CODIS) used to identify individuals. However, limitations arise when dealing with challenging samples, prompting the exploration of alternative markers such as single nucleotide polymorphisms (SNPs) and insertion/deletion (INDELs) polymorphisms. Unlike SNPs, INDELs can be differentiated easily by size, making them compatible with electrophoresis methods.
View Article and Find Full Text PDFShort tandem repeat (STR) loci are the traditional markers used for kinship, missing persons, and direct comparison human identity testing. These markers hold considerable value due to their highly polymorphic nature, amplicon size, and ability to be multiplexed. However, many STRs are still too large for use in analysis of highly degraded DNA.
View Article and Find Full Text PDFBackground: Massively parallel sequencing (MPS) technologies have the capacity to sequence targeted regions or whole genomes of multiple nucleic acid samples with high coverage by sequencing millions of DNA fragments simultaneously. Compared with Sanger sequencing, MPS also can reduce labor and cost on a per nucleotide basis and indeed on a per sample basis. In this study, whole genomes of human mitochondria (mtGenome) were sequenced on the Personal Genome Machine (PGMTM) (Life Technologies, San Francisco, CA), the out data were assessed, and the results were compared with data previously generated on the MiSeqTM (Illumina, San Diego, CA).
View Article and Find Full Text PDFSTR typing in forensic genetics has been performed traditionally using capillary electrophoresis (CE). However, CE-based method has some limitations: a small number of STR loci can be used; stutter products, dye artifacts and low level alleles. Massively parallel sequencing (MPS) has been considered a viable technology in recent years allowing high-throughput coverage at a relatively affordable price.
View Article and Find Full Text PDFForensic Sci Int Genet
November 2014
Short tandem repeat (STR) typing is used routinely for associating or excluding individuals with biological evidence left at a crime scene. Improvements have been made to reduce the turnaround time and labor involved with profile generation, but there is still some lag time between sample collection and interpretation of results. The RapidHIT(®) (IntegenX; Pleasanton, CA, USA) system is an automated instrument that is configured to perform DNA extraction, bead-based DNA normalization, amplification, electrophoresis of PCR amplicons, and data analysis of five reference swabs simultaneously.
View Article and Find Full Text PDFForensic Sci Int Genet
September 2014
Success of DNA typing is related to the amount of target material recovered from an evidentiary item. Generally, the more DNA that is recovered, the better the chance is of obtaining a typing result that will be robust and reliable. One method of collecting stain materials is by swabbing.
View Article and Find Full Text PDFMitochondrial DNA typing in forensic genetics has been performed traditionally using Sanger-type sequencing. Consequently sequencing of a relatively-large target such as the mitochondrial genome (mtGenome) is laborious and time consuming. Thus, sequencing typically focuses on the control region due to its high concentration of variation.
View Article and Find Full Text PDFBi-Allelic Insertions and Deletions (INDELs) are a powerful set of genetic markers for Human Identification (HID). They have certain desirable features, such as low mutation rates, no stutter, and potentially small amplicon sizes that could prove effective in some circumstances. In this study, we analyzed the distribution of 114 INDELs in four North American populations (Caucasian, African American, Southwest Hispanic, and Asian) to estimate their distribution in major global populations.
View Article and Find Full Text PDFObjectives: Retrotransposable elements (REs), consisting of long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), are a group of markers that can be useful for human identity testing. Until now, however, due to the inherent size difference (up to 6 kb in some instances) associated with insertion and null alleles (or INNULs), the use of REs for facilitated population studies has not been sought or practical. The size of the insertion elements (from a few hundred to several thousand bp) has proven to limit their utility as a marker because of the inefficient amplicon yield with PCR.
View Article and Find Full Text PDFThe detection of semen can assist in reconstructing the events of a sexual assault and impact the outcome of legal dispositions. Many methods currently are used for detecting the presence of semen, but they all have limitations with regards to specificity, sample degradation/consumption, stability of biomolecule assayed, and/or incompatibility with downstream individual identification assays. DNA is routinely collected at sexual assault crime scenes and is widely used for individual identification.
View Article and Find Full Text PDFMarker sets that are based on small insertion/deletion (INDEL) alleles can serve as useful supplementary or stand-alone assays for human identification. A validation study has been performed on a human identification assay based on a panel of 30 INDELs and amelogenin using the Investigator DIPplex® kit (Qiagen). The assay was able to type DNA from a number of forensically relevant sample types and obtain full profiles with 62 pg of template DNA and partial profiles with as little as 16 pg of template DNA.
View Article and Find Full Text PDFBackground: Preconditioning environments or therapeutics, to suppress the cellular damage associated with severe oxygen deprivation, is of interest to our understanding of diseases associated with oxygen deprivation. Wildtype C. elegans exposed to anoxia enter into a state of suspended animation in which energy-requiring processes reversibly arrest.
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