over time

Development of Forensic DNA Techniques Through Time

The development of forensic DNA techniques has been a game-changer for criminal investigations. DNA is a hereditary molecule that contains genetic instructions. It’s the primary factor in determining the way we look.

Although, 99.9% of our DNA is similar to other individuals; it’s the 0.1% that makes us different from other individuals therefore of primary interest to forensic scientists.

Forensic scientists generate a DNA profile from the individual’s biological samples from the crime scene. This DNA profile can be matched with reference DNA from a suspect.

Until around the year 2000, forensics techniques would not be able to generate a DNA profile from tiny samples of biological materials. With forensic DNA techniques development, the sensitivity and the ability to detect invisible biological samples have increased.

Prior to the development of forensic genetics, you would have needed a fresh sample of blood or semen about the size of a dime to generate a DNA profile.

Today, a full DNA profile can be generated from just 50 picograms of DNA (the amount presented in roughly 8 human cells.) Such traces are invisible to the naked eye.

DNA Techniques Over The Years

Size of DNA sample ⇒ Large (2 cm) blood stains Small (mm) size, visible traces Small, invisible traces Very small, invisible traces; typically touch traces
Technique ⇒ 1900
Analysis of Blood Groups (ABO & MN) and proteins.
DNA Profiling
Colin Pitchfork case – the first conviction that relied on DNA evidence.1991
Autosomal Short Tandem Repeat Profiling
This technique can generate a DNA profile in a few hours.

First DNA Databases were established.

Mitochondrial DNA
It is present in cells in more copies than other types of DNA. So, analyzing it can be useful in a mass disaster such as in a plane crash where DNA may have been damaged by heat or light.
Y Chromosomal Analysis

This analysis is useful in sexual assault cases.2000
Low Template Analysis
The most sensitive technique that can be used on the smallest sample of DNA.
Familial Searching
It uses DNA databases to match a DNA sample from the crime scene to relatives of the suspect.2003
Autosomal Single Nucleotide Polymorphism Analysis
It can be used on highly degraded DNA, like old bones.2005
Biogeographic Ancestry Testing
It provides ancestry information of large geographic regions, like African, Eurasian, and East Asian individuals.
Forensic DNA Phenotyping
It’s used to predict eye and hair color to provide investigative leads.Age Predictive Tests
This technique is used to narrow down the suspect pool by age.

Next Generation Sequencing
It aims to advance the ability to deal with mixtures of more than one person’s DNA.

Epigenetics and DNA Methylation
DNA methylation is adjusted across the genome, as a response to prolonged environmental stimuli, resulting in the individual epigenetic fingerprint. This technique broadens DNA investigation intelligence.

Genetic Genealogy
Attention has focused on genetic genealogy in a forensic context, since the arrest of Joseph DeAngelo.

Usability ⇒ no longer in use widely used widely used  in limited use                                                                                                     currently used

Final Thoughts From Sorenson Forensics

Forensic DNA techniques continue to be a dynamic, innovative, and evolving field of research. The amount of information that can be extracted from the tiniest traces of DNA also continues to grow.

It’s time to take stock of the benefits that the latest development in DNA analysis brings. The Sorenson Forensics laboratory is validated to perform the latest forensic DNA analysis techniques. We are committed to the cause of justice and victim advocacy.
Do you need forensic DNA testing help for your case? Feel free to contact us for a free consultation.

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