NCJ Number
146642
Journal
Journal of Forensic Sciences Volume: 39 Issue: 1 Dated: (January 1994) Pages: 41-51
Date Published
1994
Length
11 pages
Annotation
The Perkin-Elmer (PE) AmpliType DQ alpha Forensic Kit is available to amplify and type polymorphic regions in the human leukocyte antigen (HLA) DQ alpha sequence.
Abstract
Following amplification of the DQ alpha region with the PE kit, typing strips containing immobilized DNA probes are processed to distinguish six possible HLA DQ alpha alleles. Previous studies have shown that, in a single-source DNA sample, it is possible to detect a weak signal on the 1.1 specific allele dot when the sample's genotype clearly does not contain the 1.1 allele. Further, it has been suggested that a potential source of this weak signal is the nonspecific amplification of an HLA DX alpha gene sequence. To demonstrate the relationship between the DX alpha gene and the 1.1 nonspecific signal, the current study designed biotinylated DX alpha polymerase chain reaction (PCR) primers specific to a 178 bp region in which the amplified product spanned the homologous DQ alpha region encompassing the DNA probes present on typing strips. DX alpha DNA sequences from various DQ alpha genotypes were amplified and hybridized to DQ alpha typing strips. Results showed that DQ alpha PCR products did not always hybridize to the 1.1 probe on typing strips. Sequence analysis of DX alpha PCR products found that this region was polymorphic, explaining why the occurrence of the 1.1 weak signal was unpredictable. An analysis of the effect of DNA template concentration on the DQ alpha amplification protocol found that regulation of PCR-input DNA optimized amplification and typing protocols for HLA DQ alpha alleles and minimized potential observation of the 1.1 weak signal. 12 references and 6 figures