Update Contains Powerful Common Donor, Kinship Features

A powerful new version of DBLR™, an investigative application for rapidly calculating likelihood ratios (LRs) in DNA evidence, is being launched today.


Developed by the same team that created STRmix™ – sophisticated forensic software used to resolve mixed DNA profiles previously thought to be too complex to interpret – the new version of DBLR™ contains features which allow forensic analysts to determine whether there is a common donor between DNA samples and test any conceivable kinship relationship. 


DBLR™ (which stands for database likelihood ratios) typically is used in conjunction with STRmix™. Capable of calculating millions of LRs in a matter of seconds, DBLR™ enables users to visualize the value of DNA mixture evidence, undertake mixture-to-mixture comparisons, and achieve superfast database searches.


Likelihood ratios are used to assess the strength of DNA evidence and how likely it is that DNA found at a crime scene belongs to specific individuals.


“The Common Donor function in the new version of DBLR™ allows users to combine multiple evidence profiles in a single calculation,” says Dr. Maarten Kruijver, DBLR’s ™ developer. “This enables us to better resolve the genotype of a contributor who appears in multiple samples and search a database to identify possible matches.”


Dr. Kruijver continues, “The new Kinship feature is also very exciting. Forensic analysts can build any pedigree imaginable and calculate likelihoods for the different propositions. Both of these features significantly advance DBLR™ as a tool for generating vital intelligence information from DNA profiling evidence.”


DBLR™ also provides increased accessibility since it can run on a user’s PC without the need for high-speed computing. Other improvements in the updated version of DBLR™ include:

  • Enhanced ability to view simulations when visualizing the value of evidence;
  • Expansion of the underpinning maths that allow users to search for common contributors between mixed DNA profiles (mix-to-mix);
  • Visualization of mix-to-mix likelihood ratios using a heat map;
  • Easier loading of input files, as well as password protection of the application.

To date, STRmix™, key part of the total workflow incorporating DBLR™, has been used to interpret DNA evidence in more than 220,000 cases worldwide. That number includes numerous U.S. court cases and more than 80 successful admissibility hearings.

STRmix™ was developed by John Buckleton, DSc, FRSNZ, and Jo-Anne Bright of the New Zealand Institute of Environmental Science and Research (ESR), and Duncan Taylor from Forensic Science SA (FSSA).


The team that created STRmix™ and DBLR™ also recently launched FaSTR™ DNA, expert forensic software that rapidly analyzes DNA profiles and can assign a number of contributors (NoC) estimate.

Designed by scientists for scientists, FaSTR™ DNA combines an intuitive, user-friendly graphical interface with easily understandable and laboratory-customizable rules to expedite the analysis of raw data generated by genetic analyzers and standard profiling kits. It also optionally implements the use of artificial neural networks for peak classification independent of and in parallel to the forensic analyst.

Together, STRmix™, FaSTR™ DNA, and DBLR™ complete the full workflow(external link) from analysis to interpretation and database matching.

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