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Semen Analysis

Semen Analysis. While precise legal definitions vary by states and jurisdictions, rape is the term commonly used to mean non-consensual sexual intercourse, including vaginal, anal or oral penetration. MD Criminal Law Title 3. Other Crimes Against the Person Subtitle 3. Sexual Crimes

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Semen Analysis

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  1. Semen Analysis

  2. While precise legal definitions vary by states and jurisdictions, rape is the term commonly used to mean non-consensual sexual intercourse, including vaginal, anal or oral penetration. • MD Criminal Law Title 3. Other Crimes Against the Person • Subtitle 3. Sexual Crimes • § 3-303. Rape in the first degree • § 3-304. Rape in the second degree • § 3-305. Sexual offense in the first degree • § 3-306. Sexual offense in the second degree • § 3-307. Sexual offense in the third degree • § 3-308. Sexual offense in the fourth degree

  3. It is estimated that one in 5 women and one in 71 men are raped in their lifetimes in the United States. Together, that's more than 23.6 million survivors.

  4. Outline • Biological characteristics of semen • Spermatozoa • Detection of semen • Presumptive vs confirmatory tests • Presumptive tests for semen • Detection of sperm • “Christmas Tree” stain • Confirmatory test for semen

  5. Biological Characteristics of Semen • Typical ejaculation • 2-5 ml of semen, 160 million sperm • 3 pg DNA/sperm = 480,000 ng DNA/ejaculate • Only 1 ng DNA needed for STR typing! • Seminal fluid • Medium for ejaculation • Enzymes and other proteins • Acid Phosphatase (AP), Prostate Specific Antigen (PSA), and semenogelin • Sperm cells- Spermatozoa

  6. Gathering Evidence • Semen is an extremely good source of DNA • BUT… • Not all semen stains contain sperm • Vasectomy- blocks sperm from being ejaculated • Semen still produced • DNA typing probably not possible • Infertility • Depending on severity, DNA typing may be possible

  7. Spermatozoa • Three distinct regions: • Head – acrosome and nucleus (with haploid DNA) • Middle Piece (mitochondria) • Tail (flagella; mobility)

  8. Presumptive Tests for Semen • Semen fluoresces under ALS • UV light • Crime Lite (500 nm) • Lots of false positives Alternative light source

  9. Presumptive Tests for Semen • Acid phosphatase enzyme • Advantages • High levels in fresh semen stains • Very fast, inexpensive • Can be done in the field • Limitations • Activity may be weak or absent in older stains • Also present at low levels in vaginal fluid and bacteria • Not species-specific

  10. Presumptive Tests for Semen • Overlay method • Spray filter paper with distilled water • Lay the paper down over the suspected semen stain • Leave in contact with stain 30-60 seconds • Remove paper circle from stain and spray with AP spot solution • Look for a rapid color change to purple Positive acid phosphatase overlay assay

  11. Presumptive Tests for Semen • Spot test method • Wet sterile cotton swab with distilled water • Roll swab across stain • Saturate swab with AP solution

  12. Presumptive Tests for Semen • Prostate-specific antigen (PSA) • Major protein in seminal fluid • Also detected in urine, fecal matter, sweat, milk but at much lower levels • Half-life of dried stain: 3 years • Detected with immunochromatographic test strip assay

  13. Presumptive Tests for Semen • Immunochromatographic test strip assay • Rapid and simple • Specificity still under debate • Rapid Stain Identification (RSID-Semen)

  14. T C human semenogenlin monoclonal gold-labeled murine anti human semenogelin antibody to epitope 1 monoclonal unlabeled murine anti human semenogelin antibody to epitope 2 polyclonal unlabeled goat anti murine antiglobulin T Positive RSID™ semen test

  15. T C Negative RSID™ semen test

  16. Conclusive Detection of Sperm • Microscopic examination • “Christmas Tree” stain • Nuclear Fast Red stains nuclei red • Picroindigocarmine stains tails green Acrosomes don’t stain well in primate sperm

  17. Preserving evidence Victims should make every effort to save anything that might contain the perpetrator’s DNA, therefore a victim should not: • Bathe or shower • Use the restroom • Change clothes • Comb hair • Clean up the crime scene • Move anything the offender may have touched

  18. On February 7, 2014, Maryland Delegate Heather Mizeurintroducedlegislation that would require each law enforcement agency to report the total number of untested rape kits in its custody to the Governor's Office on April 1 of every year. HB 1341 would also require health care providers who conduct rape kit examinations to provide the survivor with contact information for the law enforcement agency with jurisdiction over her or his case. When an agency receives a request from a survivor for information about the status of the kit, they would have to respond within 30 days with the status and any results of analysis. Unfortunately, the bill did not pass before the end of the legislative session. 

  19. Rape Kit Backlog • http://www.endthebacklog.org/ • “We cannot be sure of the total number of untested kits nationwide because most jurisdictions do not have systems for tracking or counting rape kits. Only three states—Illinois, Texas and Colorado—require law enforcement agencies to count, track and test their untested kits. There is no federal law mandating a nationwide movement toward tracking and testing rape kits, despite efforts by some members of Congress to pass such legislation.”

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