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Forensic DNA Past, Present, Future Kathy Sullivan Illinois State Police Joliet Forensic Science...
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Transcript of Forensic DNA Past, Present, Future Kathy Sullivan Illinois State Police Joliet Forensic Science...
Forensic DNA Past, Present,
Future
Kathy Sullivan
Illinois State Police
Joliet Forensic Science Laboratory
Case Study: Jeffrey Knight
• Homicide from Kankakee County in December, 1997
• A head, hands and feet were found in a garbage bag in the woods
• Jeffrey Knight was suspected of killing his step mother, Marguerite, and disposing of her partially dismembered body
Case Study: Jeffrey Knight
• Screening results: many blood stains found, but only some were human
• DNA results: performed using DQ-alpha/Polymarker and D1S80
Case Study: Jeffrey Knight
• Stains found around the barn, on a reciprocating saw and the trunk and floorboard of a car match Marguerite Knight
• Random match probability is 2.1 billion Blacks, 5.4 million Hispanics and 5.3 million Whites
• Jeffrey Knight was convicted and sentenced to 60 years in prison (he is eligible for parole December 2027)
Case Study: Timothy Evans
• Summer of 2002
A series of night-time home invasions and sexual assaults begins in Joliet and Bolingbrook
• Media names the assailant the “Nightcrawler”
Case Study: Timothy Evans
• Evidence from one of the “Nightcrawler” sexual assaults is received by the lab in May 2003
• Underpants of the young victim are submitted to be tested for biological fluids (semen and saliva)
Case Study: Timothy Evans
• Testing indictes saliva on the crotch lining and the stain is removed for DNA analysis
Case Study: Timothy Evans
• DNA analysis yields a mixture of profiles consistent with the victim and one additional male contributor
Case Study: Timothy Evans
• Minor male DNA profile is entered into the DNA Index
• June 11, 2003 a match is reported to a sample from an Aurora case two years before
• The matching sample is a standard from Timothy Evans
Case Study: Timothy Evans
• Joliet Police Department is notified and on June 14th the suspect is arrested
• Confirmatory analysis verifies the match
• Random match probability of 1 in 20 billion Blacks, 1 in 310 billion Hispanics and 1 in 330 billion Whites
Case Study: Timothy Evans
15,17 15,17 19,21
X,Y 14,15 29,30 15,16
11,13 12,12 9,11
Case Study: Timothy Evans
X,Y
15,17 9,11
6,7 9,9 9,10
9,11
Case Study: Timothy Evans
• Timothy Evans pleaded guilty to the charges against him and was sentenced to 50 years in prison
• The DNA evidence and CODIS hit were instrumental in providing law enforcement with the link to the assailant
Advances in DNA Technologies
Yield Gel =how much DNA?
QuantiBlot =how much is human?
Advances in DNA Technologies
Quantification Procedure
Tells how much human DNA
AND how much male
DNA is in the sample
Advances in DNA Technologies
• RFLP
Advances in DNA Technologies
• RFLP
• PCR:– D1S80
Advances in DNA Technologies
• RFLP
• PCR:– D1S80– DQ-alpha– Polymarker
Advances in DNA Technologies
• RFLP
• PCR:– D1S80– DQ-alpha– Polymarker– STRs
Advances in DNA Technologies
• RFLP
• PCR:– D1S80– DQ-alpha– Polymarker– STRs– Y-STRs
Additional Technologies
• Mitochondrial DNA
On the Horizon
• Larger STR multiplexes
On the Horizon
• Larger STR multiplexes
• Automation – fluid handling systems
On the Horizon
• Larger STR multiplexes
• Automation – fluid handling systems
• High-throughput detection systems
On the Horizon
• Larger STR multiplexes
• Automation – fluid handling systems
• High-throughput detection systems
• Accreditation
Forensic DNA Past, Present, Future
• Kathy SullivanJoliet Forensic Science Lab515 E. Woodruff RoadJoliet, Illinois 60432815-740-3543