A new forensic tool - Novel method of Identifying a Minor Contributor’s DNA in a Mixed Sample


Executive Summary


Forensic scientists use an array of tools to identify individuals from a crime scene ranging from fingerprints to DNA. However, DNA evidence samples often contain DNA mixtures from both an assailant and a victim, which can either obscure one source or even render the entire evidence sample useless. The difficulty of de-convolving extremely unbalanced mixtures is one of the major limitations of current DNA tests. MSU researchers have addressed this issue with a an innovative method that can both resolve a minor contributor’s DNA with great sensitivity and be easily integrated with current 20 core loci Combined DNA Index System (CODIS) profiling methods.


Description of Technology


This is a method of identifying and visualizing the DNA samples of a minor contributor in a DNA mixture, using specific polymorphic CODIS STR primers. This method can enhance the effectiveness of CODIS and overcome limitations of current crime kit, especially PCR amplification bias. Successful amplification of the minor contributor will allow the STR genotype to be compared to a reference sample or CODIS database. Thus, these polymorphic CODIS STR primers will allow analysts to deconvolute and easily apply statistics to unbalanced DNA mixtures that may be uninformative otherwise.


Key Benefits

  • Can identify DNA of a minor contributor that was previously not possible using standard methods.
  • Sensitive detection (1:1000 concentration ratio) of a minor contributor’s DNA from a mixed sample.
  • Complements and enhances FBI’s CODIS capabilities.
  • Easily incorporated into existing commercially available kits.



  • Forensic Science - Identification of minor DNA contributor in mixed sample.
  • Prenatal genetic testing – Fetal DNA from mother’s blood.
  • Organ transplant – Detection of donor DNA in the recipient.


Patent Status: 


Patent Pending


Licensing Rights Available:


Full licensing rights available


Inventors: David Foran, Ph.D., Katelyn Kranz


Tech ID: TEC2018-0081


Patent Information:


For Information, Contact:

Su-Jun Lim
Technology Manager
Michigan State University