Forensic Dna Profiling
Forensic Dna Profiling - Related Videos
11:49
Enhanced Genetic Analysis of Single Human Bioparticles Recovered by Simplified Micromanipulation from Forensic ‘Touch DNA’ Evidence
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Cited by 26 •
2015
Here we describe an optimized and efficient removal strategy for the collection of bio-particles present in ‘touch DNA’ samples, together with an enhanced amplification protocol involving a one-step 5 µl micro-volume lysis/STR amplification, to permit the recovery of short tandem repeat (STR) profiles of the bio-particle donor(s).
08:04
DNA Sequence Recognition by DNA Primase Using High-Throughput Primase Profiling
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Cited by 3 •
2019
Protein binding microarray (PBM) experiments combined with biochemical assays link the binding and catalytic properties of DNA primase, an enzyme that synthesizes RNA primers on template DNA. This method, designated as high-throughput primase profiling (HTPP), can be used to reveal DNA-binding patterns of a variety of enzymes.
10:17
Profiling DNA Replication Timing Using Zebrafish as an In Vivo Model System
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Cited by 5 •
2018
Zebrafish were recently used as an in vivo model system to study DNA replication timing during development. Here is detailed the protocols for using zebrafish embryos to profile replication timing. This protocol can be easily adapted to study replication timing in mutants, individual cell types, disease models, and other species.
08:29
Expression Profiling with Microarrays
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2023
Microarrays are important tools for profiling gene expression, and are based on complementary binding between probes that are attached to glass chips and nucleic acids derived from samples. Using these arrays, scientists can simultaneously evaluate the expression of thousands of genes. In addition, the expression profiles of different cells or tissue types can be compared, allowing researchers to deduce how the expression of different genes change during biological processes, and thus gain...
05:31
Gas Chromatography-Mass Spectrometry Paired with Total Vaporization Solid-Phase Microextraction as a Forensic Tool
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Cited by 2 •
2021
Total Vaporization Solid Phase Microextraction (TV-SPME) completely vaporizes a liquid sample whilst analytes are sorbed onto a SPME fiber. This allows for partitioning of the analyte between only the solvent vapor and the SPME fiber coating.
FAQs
Forensic DNA profiling relies on STRs because these regions contain inherited patterns that can vary among individuals. During analysis, the selected STR results are considered together rather than as a single feature. This combined pattern supports comparisons between evidence and reference samples, while the inherited nature of the markers also makes them relevant to kinship assessment.
Polymerase chain reaction amplifies selected STR regions, allowing analysts to examine those targets even when the original biological evidence provides limited DNA. Amplification makes the regions suitable for fragment separation and profile generation, but it also increases the importance of contamination control. Unwanted DNA introduced during handling can affect the resulting profile and its interpretation.
Capillary electrophoresis separates the amplified DNA fragments so analysts can distinguish the STR results used to construct a profile. The separation converts amplified genetic material into an interpretable pattern for comparison with a reference sample. Its value depends on the quality of the preceding extraction and amplification steps, as well as careful interpretation of the observed results.
A profile comparison is interpreted with a statistical assessment of how likely a coincidental match would be. This probability-based evaluation adds context to an observed association and helps distinguish a strong evidentiary result from a simple visual similarity. Conclusions therefore depend not only on whether profiles agree, but also on the statistical likelihood assigned to that agreement.
A typical workflow begins with DNA extraction from biological evidence, followed by amplification of selected STR regions and separation of the resulting fragments by capillary electrophoresis. Analysts then generate a profile, compare it with reference material, and evaluate the result statistically. Quality control throughout these stages helps identify problems that could compromise a conclusion.
Mixtures may contain DNA from more than one person, making it harder to associate individual genetic patterns with particular contributors. Degradation can reduce the quality or completeness of the material available for analysis, while contamination introduces DNA from an unintended source. These conditions require cautious interpretation and reinforce the need for careful handling and quality control.
Beyond associating people, evidence, and crime scenes, the method supports missing-person identification, disaster victim recovery, and kinship analysis. In these settings, analysts compare genetic profiles from available evidence or reference samples and interpret the relationships statistically. The inherited character of STR patterns is especially relevant when direct identification is unavailable but biological relatives can provide comparison material.