Variants observed for STR locus SE33: a concordance study.
Discordance of STR typing results can be expected between kits that employ different primers for amplification. The complex motif of the SE33 locus and its flanking regions can contribute to the degree of discordant results. Sequence-dependent conformational changes can manifest as length differences under certain electrophoretic conditions and/or use of different primers. The AmpFlSTR® NGM SElect™ PCR Amplification Kit (Life Technologies, Carlsbad, CA), PowerPlex® ESX 17 system (Promega Corporation, Madison, WI), and PowerPlex® ESI 17 system (Promega Corporation) were compared for concordance of allele calls for the SE33 marker in selected samples. A total of 16 samples were identified that were discordant at one of the SE33 alleles by an apparent one nucleotide in size. While the ESX 17 and NGM SElect™ kits yielded concordant results for these 16 samples, the ESI 17 kit generated alleles that differed. The discordant alleles were observed in individuals of African and European descent. Sequence analysis revealed that the one-base difference in size is not due to an indel but is instead the result of a single nucleotide polymorphism (SNP) in the flanking region of the SE33 repeat region. Three different SNPs were observed, one of which is novel. Although these migration anomalies were observed only with the ESI 17 kit, one cannot preclude that a similar phenomenon may occur with the other kits as data sets increase. The type and degree of discordance of STR allele calls among STR kits is an important issue when comparing STR profiles among laboratories and when determining search parameters for identifying candidate associations in national databases.
Department of Forensic and Investigative Genetics, Institute of Investigative Genetics, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA.
Carey
C
Davis
Jianye
J
Ge
Jonathan
J
King
Naseem
N
Malik
Volker
V
Weirich
Arthur J
AJ
Eisenberg
Bruce
B
Budowle
D000483:Alleles; D044383:Black People / Q000235:genetics; D016172:DNA Fingerprinting; D019075:Electrophoresis, Capillary; D056426:Genetic Loci; D005819:Genetic Markers; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA
D005819:Genetic Markers