Evaluation of the DNA stability of forensic markers used in betel-quid chewers' oral swab samples and oral cancerous specimens: implications for forensic application.
Chewed betel-quid (BQ) residues are often considered vital biological evidence at crime scenes, since the human DNA extracted from the residues is actually from buccal epithelial cells and can be associated with suspects. BQ-chewing is also a risk factor for oral diseases and/or cancers. Archived medical oral-specimens can be used to identify specific individuals under adverse conditions, although STR markers are known to be unstable in various tumor tissues. This study evaluates the DNA stability of forensic marker systems in BQ-chewers' oral epithelial cells, and in archived clinical specimens of oral cancer patients. The genotypes of oral and paired peripheral blood samples in 200 subjects were compared, using the commercialized typing systems of HLA-DQA1, PM (including LDLR, GYPA, HBGG, D7S8, and GC loci), and AmpFlSTR markers (including 9 STR loci and the Amelogenin gene). The 100 healthy BQ-chewers had consistent oral swab and paired blood sample genotypes analyzed withboth DQA1/PM and STR marker systems. In the 100 oral cancer patients, one discordant result at D7S8 was found in the 600DQA1/PM-marker loci, and 25 allelic alterations with expansion or contraction were detected in the 900 STR loci. The findings herein suggest that when cancerous specimens were tested, the HLA-DQA1/PM system with point polymorphism appears more reliable than the STR system with length polymorphism. Our results also indicate that healthy BQ-chewers' oral cotton swabs containing buccal epithelial cells are useful for forensic purposes using the HLA-DQA1, PM, and STR marker systems.
Yang
Chiou-herr
CH
Department of Forensic Science, Central Police University, 56 Shu-Jen Road, Kueishan, Taoyuan, Taiwan 33334, ROC.
Hsieh
Ling-ling
LL
Tsai
Chun-wei
CW
Chiou
Fu-shyan
FS
Chou
Su-lien
SL
Hsu
Ban-dar
BD
Pai
Chung-yen
CY
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001114:Areca / Q000737:chemistry*; D004247:DNA / Q000097:blood*; D016172:DNA Fingerprinting / Q000379:methods*; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects; D005260:Female; D005554:Forensic Medicine / Q000379:methods; D005819:Genetic Markers; D005838:Genotype; D006683:HLA-DQ Antigens / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000166:cytology* / Q000187:drug effects; D010946:Plants, Medicinal; D011110:Polymorphism, Genetic; D020080:Tandem Repeat Sequences
D005819:Genetic Markers; D006683:HLA-DQ Antigens; D004247:DNA