Forensic Biology
NGS- New Generation Sequencing of DNA

NGS- New Generation Sequencing of DNA

The Towson University Human Remains Identification Laboratory (THRIL), has been providing the new-generation sequencing (NGS) along with the DNA extraction and quantitation for human body fluids and human remains in historic and cold cases. 

Alexis Garloff, research assistant at Towson University states that the NGS can aid law enforcement in solving decades old cases and provide justice for victims. In comparison to the traditional DNA profile techniques, the NGS have higher chances of finding perpetrator.

It has been claimed that the NGS has opened up a new world for the forensics, as it is providing masive services than the traditional DNA sequencing techniques.

The traditional DNA sequencing techniques like the capillary K only analyze the relative length rather than the sequence of genetic loci. On the other hand, NGS rapidly performs targeted or whole genome sequence of human, animal, plant, bacterial, and viral samples.

Also the NGS analysis provides significantly increased discrimination power, as it analyzes the whole sequence of the genetic loci, which is not done by the capillary electrophoresis.

It can also detect single nucleotide polymorphisms (SNPs), estimate ancestry, physical characteristics, determine genetic genealogical connections, etc.

The NGS is capable of producing accurate and abundant information about a DNA sample in addition to the traditional forensic markers called short tandem repeats (STRs). That means if a complete STR profile cannot be generated from evidence then NGS can be used to gain additional insight.

This technology has proved useful in solving the decades old cases, as it is capable of aiding facial reconstructions from the historical remains, differentiating twins where one twin has been suspected of a crime, and helping to solve cold cases by providing new leads. 

One of the most challenging task in a criminal investigation is to establish the identity of a deceased person, as many times only decomposed remains are found at a crime scene. As per the National Missing and Unidentified Persons System (NamUs), 4,400 unidentified bodies are recovered in the US every year and the number is keep on increasing per year.

This new technology of DNA sequencing will be helpful in recognizing these unidentified bodies as well as missing persons and give a lead to the investigation.

Talking about the sensitivity of the new technology, the NGS is a very sensitive and discriminative technique which does not require a large sample size. This provides higher chances of getting a profile from the perpetrator to enter into the CODIS.

The technology is highly useful in sexual assaults, as a complete STR profile might not be recoverable with certain cases so having the ability to gain additional information, such as identity-specific SNPs, ancestry and phenotypic information, or genetic genealogical links, can increase the chance of finding the perpetrator.

Garloff said that most forensic labs do not possess NGS capabilities, however that’s starting to change. Still the reporting nomenclature needs to be standardized, and lab analysts need to be trained in this new technology.

She added, NGS produces much more data than traditional DNA typing, and labs need to develop protocols and obtain funding to store it.

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