From this url we find Partial Match explained, below: You are not allowed to view links.
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Login 28. What is a partial match at NDIS?
A: Occasionally a partial match between a forensic profile and an offender profile is observed during a routine NDIS database search. The FBI defines a partial match as a moderate stringency candidate match between two single source profiles having at each locus all of the alleles of one sample represented in the other sample (see illustration below). A “partial match†is not an exact match of the two profiles. When evaluating whether a candidate match is viable and should be processed through to confirmation, a forensic scientist may discover that the candidate offender profile is, in fact, excluded as the possible source of the profile obtained from crime scene evidence. Because of a similarity in alleles between the forensic unknown and the candidate offender profile, the scientist may conclude that a close biological relative of the offender may be the source of the forensic unknown.
The following illustrates a hypothetical partial match as seen in the Scientific Working Group on DNA Analysis Methods (SWGDAM) Recommendations to the FBI Director on the “Interim Plan for the Release of Information in the Event of a ‘Partial Match’ at NDIS†at You are not allowed to view links.
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Locus Forensic Unknown Candidate Offender Match Stringency
D8S1179 13 13, 14 Moderate
D21S11 28, 31.2 28, 31.2 High
D7S820 12 10, 12 Moderate
D7S820 10, 12 10 Moderate
D3S1358 15, 17 15, 17 High
TH01 8 7, 8 Moderate
D13S317 9, 12 9 Moderate
D16S539 11, 12 12 Moderate
VWA 17 15, 17 Moderate
TPOX 8, 11 8 Moderate
D18S51 24 16, 24 Moderate
D5S818 9, 12 12 Moderate
FGA 24, 25 24, 25 High
29. Can partial match information at NDIS be disclosed?
Since a partial match is not an exact profile match to an offender profile and therefore cannot be subject to NDIS-defined confirmation procedures, the FBI has authorized procedures for the release of partial match information. NDIS laboratories that identify a partial match resulting from an NDIS search and wish to identify the offender profile should refer to Appendix G of the NDIS Operational Procedures Manual and contact the FBI’s CODIS Unit for further information.
30. Is there any guidance on how to address these partial matches?
At the FBI’s request, the Scientific Working Group on DNA Analysis Methods (SWGDAM) reviewed the scientific issues relating to partial matches and developed recommendations to assist in the evaluation of this information. Those recommendations are available in Forensic Science Communications at You are not allowed to view links.
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31. How successful are partial matches at locating potential suspects?
As explained in SWGDAM’s recommendations “Moderate stringency CODIS matches, in general, have very low efficiency in locating true relatives in offender databases. There is little useful probative value in the majority of partial matches using the current CODIS searching rules and algorithms. There are two main reasons for this: (1) true siblings will very rarely share alleles at all CODIS core loci; (2) as offender DNA databases get large, the number of unrelated people that do share at least one allele at all loci increases very rapidly. The original intent for allowing moderate stringency CODIS searches was the realization and acknowledgment that crime scene profiles often may be partially degraded and/or contain DNA from more than one contributor. Additionally, different primer sets may have been used between profiles. Allowing the detection of partial matches can help accommodate these two scenarios and allow the ultimate detection of full, high-stringency matches that might otherwise not have been found.†The Committee’s complete list of recommendations is available at You are not allowed to view links.
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32. Are partial matches the same as familial searches?
No. A partial match, as indicated above, is the spontaneous product of a routine database search where a candidate offender profile is not identical to the forensic profile but because of a similarity in the number of alleles shared between the forensic profile and the candidate profile, the offender may be a close biological relative of the source of the forensic profile. Familial searching is an intentional or deliberate search of the database conducted after a routine search for the purpose of potentially identifying close biological relatives of the unknown forensic sample associated with the crime scene profile.
33. Are familial searches performed at NDIS?
No, familial searching is not currently performed at NDIS. See also Familial Searching and Federal Register Vol. 73, No. 238 (December 10, 2008 at page 74937).
... see the whole document at url above for fuller explanation . . .