Forensic validation of the short tandem repeat HUMACTBP2 using capillary electrophoresis

Abstract

Experiments were performed to evaluate the forensic identification of the short tandem repeat (STR) HUMACTBP2 (human beta-actin-related pseudogene) using automated fluorescence-based capillary electrophoresis. The HUMACTBP2 is a complex tetranucleotide STR locus with more than 32 alleles in the range of 202-323 bp. The reproducibility of genetic typing using a fluorescent labeled allelic ladder was determined by comparison of the calculated fragment size after consecutive (within-day) and nonconsecutive (day to day) injection. The maximum variation in size (window) observed for any allele was 0.23 bp for the within-day and 0.8 bp for the day-to-day precision. Furthermore, it is possible to achieve a 1 bp resolution, the precision of the reproducibility assays being about 99.95%. Sixty blood samples and twenty stains were typed with both automated fluorescent sequencer ABI 373A and ABI 310. Identical genotypes were obtained with both techniques and the ABI 310 seemed to be more sensitive than the ABI 373A. A population sample of 197 unrelated individuals from southwest Switzerland was analyzed and the genotype frequencies observed were similar to those reported by others. Thirty-one alleles and 126 genotypes were found. The observed heterozygosity was 0.934. Mixtures from two different blood samples varying in their ratio were typed and the minor fraction was detectable to about 1:10. The practical usefulness of the HUMACTBP2 is illustrated by analyzing casework samples. This validation study proves the usefulness of the HUMACTBP2 locus in forensics and the detection efficiency using fluorescent capillary electrophoresis.

Forensic Science

“…Sequencing data and allele distribution for the D12S391 STR locus in an Austria population is reported (540). A validation study of the STR ACTBP2 is reported (541). Matrix-assisted laser desorption/ ionization was used for the detection of tetranucleotide STRs using a time-of-flight mass spectrometer (542).…”

Development of the AmpF?STR SEfiler PCR amplification kit: a new multiplex containing the highly discriminating ACTBP2 (SE33) locus

“…The presence of numerous interalleles in SE33, however, makes high demands on the resolving capacity of the electrophoresis device used for its analysis (Gill et al 1994). More recently capillary electrophoresis has been shown to provide better resolving capacity for the SE33 locus (Rothämel et al 2000;Dimo-Simonin et al 1998).…”

Allele typing of short tandem repeats by capillary electrophoresis

“…Due to the high voltages which may be applied to the thin-walled fused silica capillaries containing the separation medium, CE is more efficient and faster than conventional slab-gel electrophoresis and the laborintensive and time-consuming procedures intrinsic to slab gel techniques are therefore avoided. Capillary electrophoresis has recently been described as a useful tool in genomic DNA typing of the D1S80 and amelogenin loci [5][6][7], as well as short tandem repeats (STRs) [8][9][10][11][12][13][14]. With respect to early experiments, presently available instruments and software can collect and analyse DNA data and sizing may be achieved by comparing the retention times of forensic samples against molecular weight markers or the allele ladder.…”