U.S. flag
      An official website of the United States government, Department of Justice.
        Here's how you know
      Here's how you know**Official websites use .gov**
            
            A **.gov** website belongs to an official government organization in the United States.
      **Secure .gov websites use HTTPS**
            
            A **lock** (
            A locked padlock
            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. Menu

      
        close

            
            
                                              About NIJ
        
                    
  
          About NIJ
      
    
          The NIJ Director
          How NIJ Is Organized
          Mission and Guiding Principles
          Research and Development Process
          Strategic Framework
          Assessments of NIJ
          Annual Reports & Reports to Congress
          Staff Directory
          Funding & Awards
        
                    
  
          Funding & Awards
      
    
          Current Funding
          Forthcoming Funding
          Expired Funding
          Awards: Listing of Funded Projects
          Guidance for Applicants and Awardees
          Fellowship & Student Programs
          Travel Scholarships
          NIJ Challenge Program
          Library & Multimedia
        
                    
  
          Library & Multimedia
      
    
          NIJ Journal
          Podcasts
          Publications Listing
          Multimedia Listing
          Rated Practices on CrimeSolutions
          Rated Programs on CrimeSolutions
          Software & Databases
          Datasets
          Patents
          Topics
        
                    
  
          Topics
      
    
          Article Listing
          Corrections
          Courts
          Crime Prevention
          Crimes
          Drugs and Crime
          Equipment and Technology
          Forensic Sciences
          Youth Justice
          Justice System Reform
          Law Enforcement
          Tribal Crime and Justice
          Victims of Crime
          Events
        
                    
  
          Events
      
    
          NIJ 2024 Research Conference
          Scheduled Events
          On-Demand Events
          Research Meetings & Workshops
          NIJ-Hosted Online Training

                            
                                About
          Contact Us
          Subscribe
          Topics A-Z
                  Share
FacebookXLinkedInRedditPinterestEmail Home
                            Events
 Interlaboratory Comparison of SpermX and Conventional Differential Extractions

  © rawpixel-com/freepik.com (see reuse policy). Event Dates
              August 11, 2022, 1:00 pm
 – 2:00 pmEastern
Event Duration
              1 hour
Location
              online

Register
Save to calendar
Scientists from three participating laboratories - University of Central Florida (UCF), Center for Forensic Science Research and Education (CFSRE), and InnoGenomics (IGT) - will present results obtained from mock sexual assault samples analyzed using the SpermX (SX) method and their in-house differential extraction (DE) method. All three laboratories processed identical sets of female:male mixture swabs at various ratios in triplicate and will present their experiences and insights from this study.

Eight DNA mixtures were prepared with the same female (saliva) and male (semen) donors with female:male ratios ranging from 100:1 to 18,182:1. Quantification data, culled from the sperm fractions, were used to make comparisons of the total Y DNA recovered, the total human to Y ratios (short or small target to Y target, abbreviated S/Y), the percentage recovery of male in the sperm fraction relative to the theoretical amount, and the percentage of female carryover. The SX method resulted in higher yields of male DNA for all samples for all laboratories. On average, SX recovered 5 times more male DNA than did the DE method. The average S/Y ratios were lower with SX than DE, indicative of a better separation of the male component from the female component. The percentage recovery of the male DNA in the sperm fraction relative to the theoretical amount of semen placed on the swabs was higher for SX, and SX recovered significantly more sperm than DE from evidentiary swabs with as low as 100 cells (330 pg) and 25 cells (82.5 pg). The DE method exhibited higher average percent female carryover for all swab sets from all three labs, ranging from 2.8 to 10-fold more than SX.

STR data comparisons of the sperm fraction profiles include the percentage of unshared male alleles recovered, the male profile proportion observed in the STR profile, and statistical probabilities of inclusion as a likelihood ratio (LR). One of the triplicate swab set sperm fractions for each method was amplified and typed with either GlobalFiler (32 unshared male alleles) on a 3500 Genetic Analyzer or PowerPlex Fusion (31 unshared male alleles) on a 3130 Genetic Analyzer. On average, the SX method recovered 7-fold more male alleles in the STR profiles than the DE method overall. STRmix generated male profile proportions that demonstrated SX recovered higher percentages of the male component for all samples, ranging from 2 to 36-fold more than DE. The likelihood ratios from STRmix showed SX had comparable or higher LRs, ranging from 2 to 23 orders of magnitude.

In summary, the SX method outperformed the DE method across all quantification metrics used to evaluate their ability to separate the female and male DNA components effectively. This interlaboratory study demonstrates the SX method captures more male DNA with less female carryover resulting in more informative STR profiles than the conventional differential extraction method. Laboratories can benefit by processing their sexual assault kit evidence containing semen using the SpermX method to get the most from these evidentiary type samples. This is especially true for swabs containing low sperm amounts, which is often the case with forensic evidence.

**Detailed Learning Objectives**

Attendees will be introduced to the SpermX method for differential extraction of sexual assault kit evidence.
	Attendees will learn how the SpermX method compares to the conventional differential extraction method as performed by three laboratories using the same prepared female and male mixtures.
	Attendees will gain an understanding of how the SpermX method is superior for evidentiary swabs containing a very low amount of sperm.
View Full Course or Event Page
  
  
          Details
Event Type
              Webinar
    Event Option(s)
          Online,
                        On demand

Sponsor(s) / Host(s)

Forensic Technology Center of Excellence;National Institute of Justice (NIJ), U.S. Department of Justice
    Contact
          Forensic Technology Center of Excellence

  Link
              Contact the FTCoE with questions about this event

  Email
              [email protected]

  Registration Status
              Open

  Cost
              $0

  Eligibility
              Open to all

  Credits
              Certificate of Completion
    
  
Read more about
    
            DNA (Deoxyribonucleic Acid)
        Forensic sciences
        Trace DNA
        Male
        Female
        Education sciences
        Evidence analysis and processing
        Sexual assault
        Forensic Technology Center of Excellence
  
Date Created: July 8, 2022
    
          Side navigation
  

        

  
  
              NIJ 2024 Research Conference
    
      
            
            
            
      Scheduled Events
    
      
            
            
            
      On-Demand Events
    
      
            
            
            
      Research Meetings & Workshops
    
      
            
            
            
      NIJ-Hosted Online TrainingSimilar Events
        
                      DEIA: What I learned from the AAFS Diversity Outreach Committee
                  FBI Laboratory Decision Analysis Studies in Pattern Evidence Examinations
                  Discovery, Disclosure and Ethical Considerations
 Top

      National Institute of Justice

        
        
                        About NIJ
                    About NIJ
      
    
                  How NIJ Is Organized
      
    
                  NIJ Director
      
    
                  Research Disclaimer
      
    
                  Funding & Awards
                    Funding & Awards Home
      
    
                  Awards Listing
      
    
                  Current Funding
      
    
                  Guidance for Applicants and Awardees
      
    
                  Resources
                    Events
      
    
                  Podcasts
      
    
                  Publications
      
    
                  Topics
      
    
                  Multimedia
      
    
                  Reuse Policy
      
    
                  Contacts
                    Contact NIJ
      
    
                  Staff Directory
      
    
                  Submit a FOIA Request
      
    
                  File a Civil Rights ComplaintFacebook
          
                      X
          
                      YouTube
  

      810 7th St. NW, Washington, D.C. 20531
      
              Secondary Footer link menu
            Accessibility
              Plain Language
              Privacy Policy
              Legal Policies and Disclaimer
              No FEAR Act
              Freedom of Information Act
              USA.gov
              Justice.gov