forensic dna past, present, future kathy sullivan illinois state police joliet forensic science...
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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