Tri-Allelic Patterns


Three-banded or tri-allelic patterns are sometimes observed at a single locus in a multiplex STR profile. These tables of tri-allelic patterns are for scientists to "compare notes" as well as to see if certain allele combinations are more likely. Tri-allelic patterns generally fall into one of two different groups based on relative peak heights:

 

Type 1: Sum of heights of two of the peaks is equal to the third

Type 2: Balanced peak heights

We welcome your contributions in order to more fully catalog the genetic variation observed in these STR loci.


To contribute to these tri-allelic variant reports, click here.

401 total patterns reported as of 03/03/2017

[click on loci listed below for details]

Core STR Loci (272)

 

·         CSF1PO (9)

·         FGA (40)

·         TH01 (5)

·         TPOX (19)

·         VWA (26)

·         D3S1358 (11)

·         D5S818 (8)

·         D7S820 (22)

·         D8S1179 (22)

·         D13S317 (16)

·         D16S539 (13)

·         D18S51 (44)

·         D21S11 (27)

 

 

 

 

 

Other Common STR Loci (65)

 

·         D2S1338 (10)

·         D19S433 (12)

·         Penta D (12)

·         Penta E (16)

·         F13A01

·         FES/FPS (1)

·         F13B

·         LPL

·         SE33 (6)

          D10S1248 (2)

          D12S391 (2)

          D22S1045 (1)

          D1S1656 (3)

          D2S441

 

 

 

 

Y-STR Loci (64)

duplications or triplications

·         DYS19 (8)

·         DYS389I (4)

·         DYS389II (6)

·         DYS390 (1)

·         DYS391 (3)

·         DYS392

·         DYS393 (2)

·         DYS385 a/b (19)

·         DYS438 (4)

·         DYS439 (5)

·         DYS437 (2)

·         DYS448 (3)

·         DYS456 (2)

·         DYS458 (3)

·         DYS635 (1)

·         Y-GATA-H4 (1)

 

Variant Alleles

Information on Variant STR Alleles Sequenced at NIST

Some useful references with more information on tri-allelic patterns include:

Crouse et al. (1999) Analysis and interpretation of short tandem repeat microvariants and three banded allele patterns using multiple allele detection systems [published erratum appears in J. Forensic Sci. 1999 May;44(3)].  J. Forensic Sci. 44(1):87-94. They report finding 18 TPOX three-banded patterns, and one CSF1PO three-banded pattern.

Clayton et al. (2004) A genetic basis for anomalous band patterns encountered during DNA STR profiling. J Forensic Sci. 49(6):1207-1214.  They introduce the "Type 1" and "Type 2" nomenclature for tri-allelic patterns.

Butler, J.M. (2006) Genetics and genomics of core STR loci used in human identity testing. J. Forensic Sci. 51(2): 253-265.

 

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Last Updated: 03/03/2017