What is necessary (and unnecessary) for analyses of offender

databases

Forensic Bioinformatics (www.bioforensics.com)gilder@bioforensics.com

Jason R. GilderAugust 16, 2008

Offender databases

• Originally designed for convicted offenders– CODIS: Convicted Offender DNA

Index System

• Expanded – Unsolved crime samples– Arrestees– Elimination profiles

CODIS

• COmbined DNA Index System– National: NDIS– State: SDIS - fewer restrictions– Local: LDIS - fewest restrictions

• Convicted Offender Profiles in NDIS: 6,031,000

• Forensic Profiles in NDIS: 225,400

• More than 71,800 cold hits

Why analyze a database?

• Questions remain regarding the weight of a DNA database match– Random Match Probability (RMP)– Database Match Probability (DMP)– Balding & Donnelly LR– Other

• Composition of database may affect chance of a coincidental match– Presence of relatives

Structure of a DNA database

• Collection of records

• Structured Query Language (SQL) format

ID# Fname Lname Pop SSN Date D3 vWA FGA … D7

AC937 John Doe CAU 283-24-4300

5/2/02 13, 15 16, 16 21, 23 11, 14

BQ384 Jane Doe HIS 365-78-3472

7/23/03 12, 17 15, 19 25, 25 10, 10

BZ927 Frank Smith AA 312-55-1476

2/9/06 13, 15 14, 15 24, 26 12, 16

Examples of possible issues with the use of DNA databases

• Michigan v. Gary Leiterman– Evidence: blood found on victim’s hand– Cold hit to a 4-year-old boy

• R v. Sean Hoey– Evidence: explosive device– Cold hit to a 14-year-old boy

• Jaidyn Leskie inquest (Australia)– Evidence: clothing from deceased– Cold hit to a rape victim

Lab error and false cold hits

How a database can be analyzed

• Perform all pairwise profile comparisons– the “Arizona Search”

• P1 with P2, P1 with P3, P1 with P4, …, P1 with Pn

• P2 with P3, P2 with P4, P2 with P5, …, P2 with Pn

• Analyze profile similarity– Count number of matching loci and alleles– Perform kinship analyses

Arizona Match Data

• 65,493 Profiles– 122 pairs matched at 9 of 13 loci– 20 pairs matched at 10 of 13– 1 pair matched at 11 of 13– 1 pair matched at 12 of 13

Loci Ave Std Dev p-value9 103.47 10.64 0.08

10 3.06 1.68 9.6E-2311 0.05 0.23 4.4E-0512 0 0

9+ 106.59 10.83 5.8E-04

Review of Victoria State Database

Krane/Paoletti analysis: >11,000 profiles each compared to all others across 9 loci:

Shared alleles Observed occurrences 14                401

15                2716            117              1618 0

Aussie Bump

# Matching

Alleles

14 15 16 17

# Observed 401 27 1 16

300

100

20

1

Issues with the release or analysis of a DNA database

• Privacy concerns– Names, social security numbers, DNA

profiles, addresses, etc.

• Issues with analysis– Duplicate profiles, multiple databases,

presence of relatives, processing time, CODIS requirements

• Legal issues– California Proposition 69

Issue 1: Privacy concerns

• Database contains private information that should not be released

• Answer: provide anonymous profiles only

• Accomplished through one command

• SELECT D3, vWA, FGA, …, D7 FROM CODIS_DB

Issue 2: Duplicate profiles

• Many databases contain at least 10-15% duplicate profiles

• Answer: ignore duplicates in analysis

• A fairly thorough database analysis can take place with duplicates removed– Also identify potential mistyping rate

• The lab may be able to cull out duplicates from the same individual with additional information (e.g. SSN)

Issue 2b: Multiple databases

• California DOJ contains information in two databases that can be cross referenced to remove duplicates– Login DB – contains unique “CII” ID and accession

numbers of all samples for that individual– SDIS – contains accession number and profile

• Answer: JOIN the data with one command– Only select the first accession number profile

• SELECT D3, vWA, FGA, … D7 FROM SDIS JOIN LOGIN_DB WHERE (LOGIN_DB.ACCESSION1 = SDIS.ACCESSION)

Issue 3: Presence of relatives

• It is difficult to identify the presence of relatives by hand by simply looking at the CODIS records

• “There are a significant, but unknown number, of such related individuals in California’s offender database.” – Kenneth Konzack

• Answer: Exactly!

Issue 4: Processing time

• Performing an internal search of the database will take too long (a week or more) and will not allow for CODIS searches during that time

• Answer: perform an analysis on a separate computer or computers

• Pairwise database search is “embarrassingly parallel”

Issue 5: Legal issues

• Legal statutes (e.g., California Proposition 69) prohibit release of database to citizens

• Answer: 38 state statutes (including CA) allow for an outside review of their database for statistical analysis – Many require the removal of identifying

information

Questions?