Association for Criminal Justice Research

6262ndnd Semi-annual Meeting Semi-annual MeetingLong Beach, CaliforniaLong Beach, California

Forensic DNA TypingForensic DNA Typing

AdvantagesAdvantages Sensitivity of methodSensitivity of method

Polymerase Chain Polymerase Chain Reaction (PCR)Reaction (PCR)

Theoretically, one Theoretically, one billion copies billion copies generated after 30 generated after 30 cyclescycles

Forensic DNA TypingForensic DNA Typing

AdvantagesAdvantages Stability of DNAStability of DNA

Analysis of degraded Analysis of degraded samplessamples

Re-analysis of evidence Re-analysis of evidence from old, unsolved rape from old, unsolved rape and homicide cases and homicide cases

Forensic DNA TypingForensic DNA Typing

AdvantagesAdvantages Specificity of method Specificity of method

for human DNAfor human DNA

Forensic DNA TypingForensic DNA Typing

AdvantagesAdvantages Power of Power of

discriminationdiscrimination

Short Tandem Repeat DNA Profile

D3S1358: 16, 18 D5S818: 11

vWA: 17, 18 D13S317: 8, 11

FGA: 26 D7S820: 8

Amelogenin: X D16S539: 11, 12

D8S1179: 8, 13 THO1: 6, 9

D21S11: 28, 32.2 TPOX: 9, 11

D18S51: 12, 15 CSF1P0: 10, 12

D16S539: 11, 12

18.5% of Caucasians

or

One out of five Caucasians

One out of 363,500,000,000,000,000~56 million earth populations

D3S1358: 16, 18 D5S818: 11

vWA: 17, 18 D13S317: 8, 11

FGA: 26 D7S820: 8

Amelogenin: X D16S539: 11, 12

D8S1179: 8, 13 THO1: 6, 9

D21S11: 28, 32.2 TPOX: 9, 11

D18S51: 12, 15 CSF1P0: 10, 12

Forensic DNA TypingForensic DNA Typing

AdvantagesAdvantages Differential extractionDifferential extraction

Separation of female Separation of female and male DNAand male DNA

TABLE OF DNA ANALYSIS RESULTS

Sample ID D3S1358 vWA FGA AMEL D8S1179 D21S11 D18S51 D5S818 D13S317 D7S820 D16S539 THO1 TPOX CSF1P0

00D214-DJJ-3A (Stain on shirt)

16, 17 17, 18 23, 26 X, Y 11, 16 27, 28 13 10, 12 8, 11 8 NT NT NT NT

00D214-DJJ-3B (Stain on shirt)

NR 17>{18,19} NR X, Y 11,13,14,16 NR NR 10, 12, 13 NR NR NT NT NT NT

00D214-DJJ-3C (Stain on shirt)

16, 17 17 > 18 23, 26 X, Y 11, 16, (14) 27, 28 13, 20 10, 12 (13)

8, 11 8 NT NT NT NT

00D214-DJJ-3D (Blood on shirt)

15, 18 17, 19 25 X, Y 13, 14 (11, 16)

29, 30 13, 17 13 (10, 12)

12, 13 10 NT NT NT NT

00D214-DJJ-4A (Stain on shorts)

NR NR NR X NR NR NR NR NR NR NT NT NT NT

00D214-DJJ-4B (Blood on shorts)

NR NR NR X, Y 11 > 16 NR NR NR NR NR NT NT NT NT

00D214-DJJ-4C (Blood on shorts)

16, 17 17 > 18 NR X, Y 11 > 16 (13, 14)

27, 28 NR {10,12}>13 8, 11 8 NT NT NT NT

00D214-DJJ-4D (Stain on shorts)

16, 17 (15)

17, 18 23, 26 X, Y 11, 16 (13, 14)

27, 28 13 > 20 10, 12 (13)

8, 11 8 NT NT NT NT

00D214-DJJ-4E (Stain on shorts)

NR 17, 18 NR X, Y 11, 16 (13)

27 NR {10,12}>13 NR NR NT NT NT NT

00D214-DJJ-5A (Blood on watch)

15, 18 17, 19 19, 25 X, Y 13, 14 29, 30 13, 17 13 12, 13 10 NT NT NT NT

00D214-DJJ-100 Victim

15, 18 17, 19 19, 25 X, Y 13, 14 29, 30 13, 17 13 12, 13 10 9, 10 7, 8 7, 8 10, 11

00D214-DJJ-101 Suspect

16, 17 17, 18 23, 26 X, Y 11, 16 27, 28 13, 20 10, 12 8, 11 8 8, 9 7, 9 8* 7, 10

Key: See table on page 7

Forensic DNA TypingForensic DNA Typing AdvantagesAdvantages

Challenged samplesChallenged samples Analytical difficulties with Analytical difficulties with

human feceshuman feces Degradation of human Degradation of human

cells and DNAcells and DNA Estimated 17 billion Estimated 17 billion

cells are shed daily cells are shed daily from the human from the human small intestinesmall intestine

Estimated 10Estimated 101111 bacteria cells per bacteria cells per gram of feces in gram of feces in sigmoid colonsigmoid colon

Innate PCR inhibitory Innate PCR inhibitory substancessubstances

Plant Plant polysaccharidespolysaccharides

Bile acids (salts)Bile acids (salts)

Forensic DNA TypingForensic DNA Typing AdvantagesAdvantages

DatabasesDatabases CODIS (Combined DNA Index System)CODIS (Combined DNA Index System)

NationalNational 117,300 forensic unknowns117,300 forensic unknowns 2.6 million convicted felons2.6 million convicted felons 6,400 case-to-case hits6,400 case-to-case hits 16,000 case-to-offender hits16,000 case-to-offender hits

CaliforniaCalifornia 10,700 forensic unknowns10,700 forensic unknowns 347,000 convicted felons347,000 convicted felons

Los Angeles County Sheriff’s DepartmentLos Angeles County Sheriff’s Department 800 forensic unknowns800 forensic unknowns 51 case-to-case hits51 case-to-case hits 131 case-to-offender hits131 case-to-offender hits

Forensic DNA TypingForensic DNA Typing

AdvantagesAdvantagesDatabasesDatabases

California Proposition 69California Proposition 69 Requires collection of DNA samples from all felons, and Requires collection of DNA samples from all felons, and

from adults and juveniles arrested for or charged with from adults and juveniles arrested for or charged with specified crimes, and submission to state DNA specified crimes, and submission to state DNA databases; and, in five years, from adults arrested for or databases; and, in five years, from adults arrested for or charged with and felonycharged with and felony

~~30% of suspects are excluded by DNA from 30% of suspects are excluded by DNA from criminal investigationscriminal investigations

““There are more There are more things in heaven and things in heaven and earth, Horatio, Than earth, Horatio, Than are dreamt of in your are dreamt of in your

philosophy.”philosophy.”

William ShakespeareWilliam Shakespeare

LUMINOL

LUMINOL

Integrated Approach

• Crime Scene AnalysisCrime Scene Analysis

LOCARD’S EXCHANGE PRINCIPLELOCARD’S EXCHANGE PRINCIPLE

Whenever two objects come into contact Whenever two objects come into contact there is always a transfer of material. The there is always a transfer of material. The methods of detection may not be sensitive methods of detection may not be sensitive enough to demonstrate this or the decay enough to demonstrate this or the decay rate may be so rapid that all evidence of rate may be so rapid that all evidence of transfer has vanished after a given time. transfer has vanished after a given time. Nonetheless, the transfer has taken place.Nonetheless, the transfer has taken place.

Case History Woman reports to police that she was

forcibly raped by an unknown assailant Submits to a medical examination

Sexual assault kit collected Lengthy post-coital interval

Vaginal sample was negative for foreign biological material

Sexual Homicide The killing of a person

in the context of power, sexuality, and brutality.

Sexual Homicide The killing of a person

in the context of power, sexuality, and brutality.

Fantasy

Integrated Approach

• Crime Scene AnalysisCrime Scene Analysis

• Clandestine EducationClandestine Education

Countermeasures toForensic DNA Analysis?

Anecdotal evidence Apparent increase in use of condoms Assailants forcing victims to bathe after the assault