Establishing A National Dna Database

Implementing a national DNA database is no small task. A number of features must be in place before the database can be established and actually be effective. These are listed below:

■ A commitment on the part of each state (and local) government to provide samples for the DNA database;

■ A common set of DNA markers or standard core set so that results can be compared between all samples entered into the database;

■ Standard software and computer formats so that data can be transferred between laboratories;

■ Quality standards so that everyone can rely on results from each laboratory.

The technology of forensic DNA databases basically involves three parts: (1) the collection of known specimens, (2) analyzing those specimens and placing their DNA profiles in a computer database, and (3) subsequent comparison of unknown profiles obtained from crime scene evidence with the known profiles in the computer database.

All 50 states within the U.S. have now enacted legislation to establish a DNA databank containing profiles from individuals convicted of specific crimes. The laws vary widely across the states concerning the scope of crimes requiring sample collection for DNA databank entry. However, more and more states are moving towards collecting samples from all felons. In January 2003, the state of Virginia began collecting and analyzing DNA samples from all those arrested of certain violent crimes (Ferrara and Li 2004). The trend towards broader coverage of criminal DNA databases will likely continue as these resources demonstrate their value to the criminal justice system.

Law enforcement agencies search these databanks for matches with DNA profiles from biological evidence of unsolved crimes. Using these databanks, law enforcement agencies have been successful in identifying suspects in cases that would likely be unsolvable by any other means (e.g., the Montaret Davis case described in Chapter 1).

A number of other countries around the world have also launched national DNA databases (Martin et al. 2001, Schneider and Martin 2001, Martin 2004). The earliest national DNA databank, and so far the most effective, was created in the United Kingdom in 1995. In the first five years, more than 500 000 DNA profiles were entered into the database and more than 50 000 criminal investigations were aided (Werrett and Sparkes 1998). As of 2004, the UK National DNA Database (NDNAD) contains more than two million profiles (see http:// www.forensic.gov.uk, Asplen 2004).

COMBINED DNA INDEX SYSTEM (CODIS)

The FBI started CODIS as a pilot project in 1990 that served just 14 state and local laboratories. It took several years to gather enough DNA profiles from convicted offenders to reach the critical mass necessary to obtain matches for crime scene evidence. During the 1990s, the number of samples in CODIS grew to several hundred thousand. In addition, the number of laboratories submitting data increased. As of April 2004, CODIS software was installed in 175 public laboratories around the United States giving them the capability to submit DNA profiles to a national DNA database. In addition, 31 laboratories in 18 foreign countries also use the CODIS software.

Within CODIS there are two primary sample indexes: convicted offender samples and forensic casework samples. There is also a population file with DNA types and allele frequency data from anonymous persons intended to represent major population groups found in the United States (Budowle and Moretti 1998, Budowle et al. 2001a). These databases are used to estimate statistical frequencies of DNA profiles using the program PopStats (see Chapter 20). A missing persons index is also included in the U.S. national DNA database.

DNA profile information inputted into CODIS over the years has included restriction fragment length polymorphism (RFLP) loci and polymerase chain reaction (PCR)-based markers HLA-DQA1, PolyMarker, and D1S80. More recently, the 13 CODIS core STR loci are required for data entry into the national level of the U.S. DNA database (Budowle et al. 1998). These 13 STR markers were reviewed in Chapter 5 and provide a random match probability of approximately 1 in 100 trillion.

CODIS is not a criminal history information database but rather a system of pointers that provides only the information necessary for making matches. Only a unique identifier and the DNA profiles for a sample, such as the 13 STR loci shown in Table 18.1, are stored in CODIS. No personal information, criminal history information, or case-related information is contained within CODIS.

When CODIS identifies a potential match, the laboratories responsible for the matching profiles are notified and they contact each other to validate or refute the match (Niezgoda and Brown 1995, Niezgoda 1997). After the match has been confirmed by qualified DNA analysts, which often involves retesting of the matching convicted offender DNA sample, laboratories may exchange additional information, such as names and phone numbers of criminal investigators and case details. If a match is obtained with the Convicted Offender Index, the identity and location of the convicted offender is determined and an arrest warrant procured.

The primary metric for CODIS is the 'hit', which is defined as a match between two or more DNA profiles that provides the police with an investigative lead (or an 'investigation aided' lead) that would not otherwise have developed. Through April 2004, there have been more than 16000 investigations aided using CODIS allowing thousands of crimes to be linked and solved around the United States. Because the number of hits is largely related to the size of the database, as CODIS continues to grow, so will its value. For example, England's national DNA database maintains a 40% chance of obtaining

Table 18.1

Example of the STR profile information stored in the CODIS DNA database for a single sample. Note that there is no personal information that can be used to link an individual to his or her DNA profile. The two alleles for each STR marker are placed in separate columns labeled value 1 and value 2. For markers with homozygous results, both value 1 and value 2 are the same, see for example CSF1PO. The information in the 'sample info' field can be related to a known individual only by the originating forensic DNA laboratory.

Sample Info

Sample #

Category

Tissue

Tissue Form

Population

Type

F130

1

Convicted

Blood

Stain

Caucasian

Offender

Marker

Value 1

Value 2

Date

Time

AMEL

X

Y

15-FEB-2000

17

38:30

CSF1PO

10

10

15-FEB-2000

17

38:30

D13S317

11

14

15-FEB-2000

17

38:30

D16S539

9

11

15-FEB-2000

17

38:30

D18S51

14

16

15-FEB-2000

17

38:30

D21S11

28

30

15-FEB-2000

17

38:30

D3S1358

16

17

15-FEB-2000

17

38:30

D5S818

12

13

15-FEB-2000

17

38:30

D7S820

9

9

15-FEB-2000

17

38:30

D8S1179

12

14

15-FEB-2000

17

38:30

FGA

21

22

15-FEB-2000

17

38:30

TH01

6

6

15-FEB-2000

17

38:30

TPOX

8

8

15-FEB-2000

17

38:30

VWA

17

18

15-FEB-2000

17

38:30

a match between a crime scene profile and a 'criminal justice' (arrestee or suspect) profile loaded into the database (Asplen 2004).

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