ParaDNA® technology

Asymmetric PCR amplification

Asymmetric PCR utilizes a limiting amount of one of the amplification primers in order to generate primarily a single-stranded DNA template. The amplified and targeted single-stranded DNA template enables the use of HyBeacon® probes technology to determine the size of the amplified material.

 

HyBeacon® probes melt curve detection

HyBeacon® probes are short nucleotide sequence DNA probes that contain a fluorophore that is covalently attached via a linker group to a nucleotide on the probe.

HyBeacon® probes generate significantly higher fluorescent signals when bound to a target strand of DNA. When used in conjunction with single strand DNA templates generated during asymmetric PCR, these probes can be used to identify the size of the fragments (and ultimately the STR allele).

During melting of the HyBeacon® probe/single-stranded DNA template complex, the higher the melt temperature, the longer the fragment and allele size.

STR typing by HyBeacon® probes melt detection is a proprietary technology developed by LGC Forensics.

 

Software interpretation

The ParaDNA® system generates two pieces of information to aid investigators in deciding if a sample should be processed further in a full STR workflow:

  • Percentage score—the percentage score is a value from 0% to 100%, which is a relative indicator of the quality and quantity of human DNA present within the samples. The score is a composite of each of the 4 wells on the screening test, and can be used as an objective value to prioritize different pieces of evidence for further analysis. The higher the score, the higher the quality of the human DNA present in the sample.
  • Gender determination—One of the four PCR reactions occurring in the ParaDNA® Screening Test is targeted toward the Amelogenin gender determining region. Using these loci, the system can quickly identify the likely gender of the sample contributors, which can be important when looking for the presence of male human DNA in the sample and as an aid in victim inclusion/exclusion testing efforts.

 

For more information, contact your Life Technologies sales representative or request more information.


* For Forensic and Human Identity Applications Only.