The purpose of this research was to answer: (1) what is the period for DNA recovery in post-coital samples from the vagina and cervix using Y-STR laboratory methods, and (2) what are the common physiological conditions that may influence recovery of DNA in post-coital samples from volunteer proxy-couples.
On receipt of the Post-coital DNA Recovery Kit, the couple began coital abstinence according to the protocol. The definition of abstinence for the purposes of this study was 10 or more days of barrier methods for intimate activities, which included digital coitus, cunnilingus, and penile-vaginal intercourse. Under the protocol and before the first unprotected DNA deposit after the 10-day abstinence, the female collector nurse took baseline samples from the buccal surfaces of the male and female couple-participants. At the same time, the collector RN took baseline samples from the cervix and posterior fornix as controls. One unprotected coitus followed by abstinence with sample collection occurred at Days 4, 7, or 9, depending on one of four 10-day periods of abstinence. Once collected, samples packaged according to the study protocol used the assigned unique identifier, and collectors or participants mailed the contents directly to the National Center for Forensic Science DNA laboratory for indexing and analysis using of Y chromosome markers (Y-STR) methods.
Each subject was required to complete a data set that provided their identifying information, which remained confidential and in a secure location, available to the Principle Investigator (PI), but blinded to the laboratory and evaluation researchers. Labeling all samples in the kit, the unique number with password protection was the common thread for entering data from the laboratory, providing another layer of confidentiality where other systems' protections were in place.
A focus group of national experts in emergency and women's health care delivery gathered to identify themes for inclusion and exclusion criteria for couples, and define variables to study, as well as develop the protocol for sample collection reflecting current research and demonstrating clinical research rigor.
A nationwide recruitment of registered nurse specimen collectors occurred. Those interested recruited volunteer proxy couples in their area; for forensic nurses or nurses interested in participating as subjects, they recruited collectors. Recruitment and screening questions eliminated those with full hysterectomy (must have a cervix), male vasectomy or infertility (must have sperm DNA) and obesity (which lowers sperm count). If not self-eliminated, interested couples and collectors contacted the Principle Investigator (PI) or co-investigator where a telephone discussion about the study and protocol for IRB approved informed consent occurred. Participants received consent paperwork following the telephone consent. Once the PI received the signed consents from both couple-members, each participant completed the questionnaire and demographic survey. The PI determined eligibility and if eligible, sent a protocol kit, protocol diary and collector forms, and study directions to the female participant.
A focus group of subject matter experts convened to identify themes from their practice, learned from published literature to establish variables of interest in post-coital DNA recovery efficacy. The focus group consisted of persons with extensive experience in care of rape victims, including an emergency room physician specializing in medical forensic response to patients, a family nurse practitioner/midwife/attorney, a nurse midwife, an expert nurse in genetics, a women's health expert in vulvar diseases, and a family nurse practitioner.
Monogamous couples in the United States.
coded on-site observation
The data files "AlleleRecovery Jun 2014 Allrec.sav" (n=70; 34 variables) and "AlleleRecovery Jun 2014 Used for descriptve analysis.sav (n=66; 58 variables)" contain variables related to cervix and fornix analysis.
The data file "Condom_collections-baseline-d9-Jun2014 Allrec without open-ended-ICPSR.sav" (n=70; 66 variables) contains variables related to condom use, Hymen Estrogen Response Scale (HERS) scores, cervix analysis, menses, and illness and stress during the study period.
The data files "DNADemogFemalesJun2014- without open-ended AllRec-ICPSR.sav" (n=73; 67 variables) and "DNADemogFemalesJun2014- without open-ended -For analysis with group variables-ICPSR.sav" (n=66; 73 variables) contain demographics, as well as information on drug use, sexual history, gynecological health history, and sexually transmitted disease history.
The data file DNADemogMalesJun2014- without open-ended AllRec-ICPSR.sav (n=73; 46 variables) contains demographics, as well as information on drug use, sexual history, male sexual health history, and sexually transmitted disease history.
The data file dnalong.sas7bdat (n=264; 7 variables) contains observation day and observation sequence. It also has variables related to whether any of the following were detected:
- reports of menses during collection period
- reports of oral contraceptive use
- DNA recovery from cervix or fornix using Y-STR
- DNA recovery from cervix or fornix using enhanced Y-STR
Hymen Estrogen Response Scale (HERS)