Forensic Spermatozoa Detection

Abstract

Semen is crucial evidence for some sex crimes, with its sole confirmation being sperm detection. The success of sperm detection is dependent on all levels of preanalytic and analytic procedures. Specimen collection must be performed by well-trained and competent forensic physicians as well as forensic nurses, with preservation done properly before laboratory transfer. Laboratory procedures should consider archival sperm identification, by visualization, with adequate amounts separated from other cells to obtain male DNA profiles. Differential extraction is robust and accepted as the forensic standard but is time consuming and may result in male DNA loss. Thus, alternative methods and microdevices have been developed. Challenges in sperm isolation from vaginal or buccal epithelium mixes and discrimination in multiperpetrator cases have been overcome by single-cell profiling; however, problems inherent in identical twin discrimination and azoospermia have yet to be solved. Epigenetics and future molecular biomarkers may hold the key; therefore, all laboratory processes must consider DNA and RNA protection. Long-term specimen preservation should be done when possible in light of future confirmatory tests.

DNA Transfer in Forensic Science: Recent Progress towards Meeting Challenges

“…Corradini et al [100] showed that buccal cells collected directly on to FTA mini cards (GE Healthcare) and stored for 11 years still provided good quantities of DNA and good-quality DNA profiles. In addition to these studies, Suttipasit [55] emphasised the need for appropriate long-term specimen preservation in order to be able to take advantage of potential future methodological advances to interrogate samples beyond current abilities.…”

“…A study by Kishbaugh et al [53] of 50 vaginal swabs from unique donors over the age of 18 years and relevant history, and a study by Sari et al [54] of 20 pre-pubescent (3-9 years), 20 post-pubescent (16-45 years) and 20 post-menopausal (50-75 years) females, help fill this knowledge gap, and thus, assist the accuracy of interpretation of immunochromatographic testing results. In addition, a review of current methods of sperm detection, factors affecting sperm detection, and recent advances in sperm detection utilising alternative methodologies is provided by Suttipasit [55].…”

Comparative Study of Acute Anogenital Injury Between Consensual and Nonconsensual Postmenarche Adolescents

“…However, redness and swelling were not used as statistical data in the results. The anogenital area was divided into 10 subgroup sites: (1) labia majora, (2) labia minora, (3) hymen at 3-or 9-o'clock position, (4) hymen below 3-to 9-o'clock position, (5) Cotton swabs were used to collect evidence at the external and internal areas of the genitalia and anus. Blood and genital and culture swabs for STIs were obtained.…”

“…(3) consensual or nonconsensual; (4) macroscopic inspection and/or use of colposcope and/or toluidine staining; (5) recording and interpretation of type of wounds by TEARS classification (T = tear, laceration, or incision; E = ecchymosis; A = abrasion; R = redness; and S = swelling) 20 ; (6) inclusion or exclusion of anal injury; and (7) time since incident (TSI).…”

Generating aptamers towards human sperm cells using massively parallel sequencing

“…These assays, developed as part of the Sperm Hy-Liter product range, use anti-sperm monoclonal antibodies functionalised with Alexa 488 fluorophores to label sperm cells, allowing them to be visualized on glass slides using standard fluorescence microscopy [ 7 ]. However, despite initial promise, these techniques have yet to be widely adopted by the forensic community due to the high cost associated with antibody-based testing reagents [ 8 ].…”