Actual sperm released from a substrate may be as low as ______ of sperm deposited in stain
Certain substrates, such as cotton, hold on to sperm better than others
What are the 2 techniques for generateing a DNA profile from stained slides?
1. xylene bath to remove coverslip/mounting mediua, tranfer bio material to extraction tube by scraping/swabbing
2. laser capture microdissection
Who collects sexual assault kit samples?
- ER doctors
- SANE nurses (Sexual Assualt Nurse Examiner)
- Most major hospitals
How long do Sexual Assault kits take to collect?
How long does it take to analyize a kit?
several hours to several months
How long are the kits retained?
- Until the case has been adjudicated
- until statue of limitaions has expired
- indefinietly in homicide cases
- maybe discarded sooner if victims requests or if case isnt reported to police
What are the steps?
- Control swabs
- Toxicology testing
- Known blood sample
- Oral swabs/smears
- Fingernail scrapings
- Foreign material collections
- clothing collections
- head/pubic hair combings
- head/pubic hair standards
- genital,perianal, vaginal and anal swabs and smears
Why is time since intercourse important?
- -When IDing the presence of semen isnt enough
- -a consensual partern may be a factor
- -sperm cells can be unrealted to assualt
- -aides in establishing time/circumstances of death
Typical post-coital interval (PCI)
intact sperm in vagina
PCI sperm heads
PCI sperm heads in cervix
PCI P30 in vagina
PCI AP in vagina
Studies show that ____% of rapists do not ejaculate after _____ minuites of vaginal penetration
The vagina is a ___ enviornment
the cervix is a ______ environment
T/F Semen identified on anorectal swabs indiacts anal penetration
- –Could be a result of contamination from vaginal
- –Could be due to collection technique when
- inserting swabs into the rectum
What factors effect PCI?
- Stage in menstrual cycle
- collection technique
- washings, swabs, smears, liquid saliva
- temp and humidity