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Familial DNA Searching - an Emerging Forensic Investigative Tool

NCJ Number
Date Published
January 2019
9 pages
This article reports on the methodology and findings of the National Survey of CODIS Laboratories, which solicited information from U.S. crime labs regarding their perceptions, policies, and practices related to the use of familial DNA searching (FDS), which is a forensic technique for identifying family members through DNA databases.
FDS has the following two primary components: 1) a software comparison of a DNA profile from an unknown contributor with known profiles from a DNA database (e.g., CODIS convicted offender profiles), and 2) lineage testing to further support relatedness. The software uses genetic algorithms to identify patterns in similarity that are likely to occur within close family relationships (e.g., parent/child, siblings). An important subsequent step is lineage testing, which further supports or refutes biological relatedness between the unknown evidence sample and candidate samples identified through the database. Out of 103 crime labs that completed the survey (77-percent response rate), labs in 11 states reported using FDS, and labs in 24 states reported using a similar, but distinct practice of partial matching. Although the majority of labs had positive perceptions of the ability of FDS to assist investigation, labs also reported a number of concerns and challenges in implementing FDS. Respondents reported using either practice a limited number of times, with modest numbers of convictions resulting from both FDS and partial matching. Most labs that used these tools reported having publicly available policies and/or training to guide criminal justice staff in the use of these tools. All FDS labs had specific processes for approving a request to perform FDS. 10 figures and 28 references

Date Published: January 1, 2019