Objective Computer Assisted Review of DNA Evidence

Dan E. KraneWright State University, Dayton, OH 45435

The business of DNA profiling:

Roughly 900,000 felony convictions per year in US

DNA profiles generated primarily for sexual offenses, murder and assaults.

Combined DNA Index System (CODIS)

Less than 1% of DNA profiles reviewed by defense experts

DNA profiling approaches:

VNTRs

PCR/reverse dot blots

STRs

Advantages Disadvantagesresolving power, inexpensive

testing time, sensitivity, data comparisons

sensitivity, testing time, data comparisons

resolving power, mixtures

very sensitive, testing time, data comparisons, resolving power

start-up costs

DNA contents of biological samples:Type of sample Amount of DNA

Hair:

Blood 30,000 ng/mLstain 1 cm in area 200 ngstain 1 mm in area 2 ng

Semen 250,000 ng/mLpostcoital vaginal swab 0 - 3,000 ng

plucked 1 - 750 ng/hairshed 1 - 12 ng/hair

Saliva 5,000 ng/mLUrine 1 - 20 ng/mL

2

2

Allele 2

Allele 7

Allele 12

Allele 13

Allele 17

Primer bindingsite

Tandemly repeated

sequences

Amplified region

Short Tandem Repeats (STRs)

What you see when you open a CD provided in discovery:

What you see when you try to open the files on a discovery CD:

An electropherogram using the software’s default settings:

GenoTyper Graph

What the testing lab provides is not always the same as the default electropherogram:

Genophiler Zoom

• Genophiler also provides a zoomed graph to 150 RFU’s• Shows smaller peaks more clearly• Here, the peaks that were disregarded by the lab may be evidence of an unknown, minor contributor to the sample

No mention of a potential, secondary contributor to the sample.

Still no mention of a potential, secondary contributor to the sock sample.

Victim Run:Sample Nickname1:F011542 03P.fsa ALLEGED VICTIM OL (99) 14 (237) 15.2 (309)1:F011542 04A P.fsa SUSPECT STAIN CARD 15 (1120) 17 (1351)1:F011542 02E1P-2.fsa TOWEL CUTTING (Non-sperm Fraction) 15 (1611) 17 (1255)1:F011542 02E2P-2.fsa TOWEL CUTTING (Sperm Fraction) 15 (868) 17 (802)1:F011542 02E2 Pr.fsa TOWEL CUTTING (Non-sperm Fraction) 15 (1740) 17 (1644)1:F011542 01P.fsa SOCK CUTTING OL (125) 14 (2622) 15.2 (2189) 19 (167) OL (140)1:F011542 04 raP-2.fsa 15 (278) 17 (167)

D3

Genophiler output:

Testing lab’s report:

16 (253) 20 (184) 12 (368) 13 (350) 9 (285) 12 (281) 10 (359)14 (1130) 19 (949) 12 (1626) 13 (1565) 8 (1561) 12 (1148) 10 (895) 11 (944)14 (1495) 19 (1223) 12 (2932) 13 (2703) 8 (2423) 12 (2161) 10 (1267) 11 (1078)14 (1026) 10 (114) 12 (1272) 13 (1052) 8 (1070) 12 (838) 10 (760) 11 (709)14 (1755) 19 (1531) 12 (1874) 13 (1617) 8 (1652) 12 (1328) 10 (1250) 11 (1178)9.2 (73) 16 (628) 20 (483) 12 (2907) 12 (926) 10 (1187)14 (135) 19 (97) 12 (158) 13 (122)

D18 D5 D13 D7

15 (242) 16 (264) 21 (300) 22 (269) X (529) 12 (272) 13 (280) 27 (277) 28 (269)18 (1216) 19 (814) 21 (1352) 22 (1271) X (1347) Y (1288) 15 (2554) 29 (2687)18 (1128) 19 (899) 21 (1906) 22 (1837) X (1907) Y (1756) 15 (3885) 16 (70) 29 (4458)18 (767) 19 (564) 21 (858) 22 (541) X (1191) Y (1187) 13 (81) 15 (2242) 16 (97) 29 (2027)18 (1595) 19 (1166) 21 (1817) 22 (1154) X (1842) Y (1858) 15 (3364) 29 (3355)15 (1290) 16 (1144) 21 (1430) 22 (1394) X (5015) 12 (3418) 13 (2876) 27 (1020) 28 (1032) 30 (72)18 (153) 19 (190) 21 (230) X (196) Y (287) 15 (403) 29 (352)

D21D8vWA FGA Amel

Victim Run:Sample Nickname1:F011542 03P.fsa ALLEGED VICTIM OL (99) 14 (237) 15.2 (309)1:F011542 04A P.fsa SUSPECT STAIN CARD 15 (1120) 17 (1351)1:F011542 02E1P-2.fsa TOWEL CUTTING (Non-sperm Fraction) 15 (1611) 17 (1255)1:F011542 02E2P-2.fsa TOWEL CUTTING (Sperm Fraction) 15 (868) 17 (802)1:F011542 02E2 Pr.fsa TOWEL CUTTING (Non-sperm Fraction) 15 (1740) 17 (1644)1:F011542 01P.fsa SOCK CUTTING OL (125) 14 (2622) 15.2 (2189) 19 (167) OL (140)1:F011542 04 raP-2.fsa 15 (278) 17 (167)

D3

Mix X/Y Deg. R Low (<150) Pull Up Nickname Run:SampleM1 -0.0206 1 0 ALLEGED VICTIM 1:F011542 03P.fsa

1.05 -0.0153 0 0 SUSPECT STAIN CARD 1:F011542 04A P.fsa1.09 -0.0528 1 0 TOWEL CUTTING (Non-sperm Fraction) 1:F011542 02E1P-2.fsa

M2 1.00 -0.0221 3 0 TOWEL CUTTING (Sperm Fraction) 1:F011542 02E2P-2.fsa0.99 -0.0101 0 0 TOWEL CUTTING (Non-sperm Fraction) 1:F011542 02E2 Pr.fsa

M3 -0.0823 4 0 SOCK CUTTING 1:F011542 01P.fsa0.68 -0.0724 3 0 1:F011542 04 raP-2.fsa

Genophiler also flags potential problems for further review:

Project Screen Button

• Screen shot of GeneScan

• Shows exactly what samples were added and what parameter files were used for the analysis

Analysis Parameters Buttons

• See exactly what analysis settings were used

• Parameter files also copied to CD

Finding Problems With Samples: Raw Data

Good raw data begins with a large peak followed by smaller peaks

Finding Problems With Samples: Raw Data

• Bad raw data is indicated by wildly uneven peaks• Indicates lab analysis problems

Finding Problems With Samples: EPT Data

• Shows current, voltage, laser power, and temperature• For good analysis, should be constant (flat)

Finding Problems With Samples: EPT DataFinding Problems With Samples: EPT Data

• Problem EPT data is not flat• Indicates problems with lab analysis

Automation Process

• Select samples and settings in one screen

• Analysis can be performed unattended

• Up to 4 analysis runs can be set up at one time

Forensic BioInformatic Services• Uses Genophiler to generate easily interpreted files

• Objectively applies analysis parameters to all samples

• Fast turn around times

• Efficiently draws attention to problems requiring further review

Acknowledgements:

Genophiler programmers: Dr. Travis Doom Dr. Mike Raymer Dr. Oscar Garcia Jason R. Gilder

STR experts: Dr. Bill Thompson Dr. Simon Ford Dr. Dan Krane

Support:Wright State University, Dayton, OH

Forensic BioInformatic Services; Suite 150, 2850 Presidential Drive, Fairborn, OH, 4538x; phone: (937) xxx-xxxx; web site: BioForensics.com