Familial Searching

Process

There are two parts to the familial search process. First, the software searches available DNA profiles in the offender databank to identify candidate offender relatives and then ranks them in the order of their potential to be a close relative of the person whose DNA is at the crime scene. Next, the list is evaluated and the matches with the highest likelihood of identifying a familial connection (typically father to son or brother to brother) undergo additional DNA typing: Y-chromosome testing.^2,3 A match between Y-STR profiles in this second step of the process can strongly establish the existence of a close familial relationship between the candidate offender and the person whose DNA is in the evidence searched.

This link will play an audio file containing a description of the familial searching process. Click to read a description of the familial searching process.

Click to view an animation of the familial searching process.

² Edmund G. Brown Jr., Attorney General, DNA Partial Match (Crime Scene DNA Profile to Offender) Policy, Bureau of Forensic Services (Jan. 2008) PDF download: 48kB
³ The State of Colorado’s DNA Familial Search Policy, Colorado Bureau of Investigations policy statement, 10/22/09 PDF download: 640kB