Every two minutes, somewhere in the United States, a person is sexually assaulted.¹ Additional crime statistics estimate that males are responsible for 80% of violent crimes and that males commit approximately 95% of sexual offenses.² Sexual assault crimes account for more than 50% of biological evidence submitted to most forensic casework laboratories, and in approximately 43% of those cases, there is a known suspect.³
The evidence collected typically consists of complex mixtures of body fluids and/or tissue, often with low levels of male suspect DNA and a high background of female victim DNA. Crime laboratories have traditionally employed a differential extraction method to separate spermatozoa from non-sperm cells, segregating male and female DNA for autosomal STR analysis. This method has proven very successful, but may produce ambiguous or inconclusive results in a sizable percentage of cases, yielding approximately 19% incomplete male profiles, 19% challenging mixture profile, and 12% null male profiles.³
Difficulties obtaining a male profile are also encountered in situations involving males who have been vasectomized or who produce azoospermic semen, and for samples with multiple male contributors. Additionally, low levels of male DNA originating from bodily fluids other than semen may be encountered in evidence associated with violent crimes such as fingernail scrapings and weapon handles.
The AmpFℓSTR Yfiler PCR Amplification Kit was developed by Applied Biosystems to address these challenges. When used in conjunction with the Quantifiler Duo kit, the Yfiler kit provides an efficient and robust solution for laboratories dedicated to resolving complex cases.
Presentation: Guidelines for Interpreting the Significance of Y-STR Haplotypes Derived from Forensic Evidence (unabridged Version)
Presented by Bruce Budowle, PhD, FBI Academy, Laboratory Division on October 4, 2007 at the 18th International Symposium on Human Identification
Yfiler Kit Product Page
Yfiler Haplotype Database
United States Y-STR Database
Y Chromosome Haplotype Reference Database (YHRD)
Forensic News is a quarterly e-newsletter from Applied Biosystems, which provides the latest information on human identification applications.
NIST STRBase Y-STR Web Site
The National Center for Victims of Crime (NCVC)
The National Center for Victims of Crime is the nation's leading resource and advocacy organization for crime victims
Rape, Abuse and Incest National Network (RAINN)
The Rape, Abuse & Incest National Network is the nation's largest anti-sexual assault organization. RAINN operates the National Sexual Assault Hotline and carries out programs to prevent sexual assault, help victims and ensure that rapists are brought to justice.
|Bureau of Justice Statistics (BJS), U.S. Department of Justice, 2001
|Survey conducted by Applied Biosystems at the 18th International Symposium on Human Identification, Oct. 1-4, 2007, Hollywood, CA; 288 respondents