SE33 (ACTBP2)
Definition
An extremely polymorphic STR locus with over 90 known alleles, included in ESS17 but not in CODIS 20. Provides high discriminatory power but has a high stutter rate requiring elevated stutter thresholds.
- Allele count
- Over 90 known alleles
- Locus type
- Highly polymorphic tetranucleotide-adjacent complex STR
- Standard set membership
- Included in ESS17
- CODIS 20 status
- Not included
- Technical caveat
- High stutter rate requires elevated stutter thresholds
Common questions
Why is SE33 valued despite its technical difficulty?+
Its very high number of alleles gives it exceptional discriminatory power compared to most STR loci, so including it in a profile substantially reduces the random match probability, which is why European kits retain it even though it is harder to interpret than simpler loci.
Why is SE33 absent from the US CODIS 20 core loci while present in the European Standard Set?+
CODIS core loci were chosen partly for cross-laboratory interpretation consistency and stability of allele calling, and SE33's complex repeat structure and elevated stutter made it a less attractive candidate for the US core set, whereas European forensic genetics developed the expertise and kits to manage it as a workhorse locus.
What practical problem does SE33's high stutter rate cause in mixture interpretation?+
Stutter peaks can be mistaken for a genuine minor contributor allele in a DNA mixture, so analysts must apply a higher stutter filter threshold at SE33 than at simpler loci, and even then borderline mixture calls at this locus require extra caution.
Related terms
- Amelogenin
- A gene on both the X and Y chromosomes used for sex determination in forensic STR kits. The X-allele amplicon is approximately...
- CODIS (Combined DNA Index System)
- The FBI-managed software architecture for the US national forensic DNA database, operating through a three-tier structure of local (LDIS), state (SDIS), and...
- DNA Technology Bill 2019
- India's pending legislation proposing the creation of a national DNA database (NDDB) and a profiling regulatory framework. Passed the Lok Sabha in...
- ESS (European Standard Set)
- The set of STR loci required for profiles entered into EU national databases participating in Prüm cross-border DNA exchange. Currently aligned with...
- INTERPOL DNA Gateway
- INTERPOL's secure server for cross-national DNA profile comparison, hosted in Lyon. As of 2023, fifty-nine member countries contribute profiles.
- NDIS (National DNA Index System)
- The uppermost tier of the US CODIS architecture, holding profiles contributed by all US federal and state DNA database programs. As of...
- Prüm Decisions
- EU Council Decisions 2008/615/JHA and 2008/616/JHA requiring EU member states to allow automated cross-border DNA database comparison using a hit/no-hit system.