title: Increasing Allele Detection by Altering the Quantity of Internal Lane Standard.
abstract: Electrokinetic injection (EI) is the primary method used in forensic laboratories to load amplified PCR product in capillary electrophoresis for short tandem repeat (STR) fragment separation. Because all samples subjected to capillary electrophoresis use internal lane standard (ILS), this study investigated the consequence of varying the volume of ILS and its effects on allele peak heights and number of alleles detected. Results demonstrated that when the volume of ILS is reduced, the average peak height and number of alleles increased, thereby increasing the sensitivity of the detection method. Sizing anomalies were observed; however, they did not adversely affect accuracy and precision. The method developed in this study offers a simple and universal procedure to increase the alleles detected in forensic STR analysis. Reducing the volume of ILS to achieve greater sensitivity is applicable to all STR amplification kits and capillary electrophoresis instruments currently used in forensic DNA analysis.
authors.affiliation: North Louisiana Criminalistics Laboratory, 1115 Brooks Street, Shreveport, LA, 71101.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Esparza
authors.affiliation: North Louisiana Criminalistics Laboratory, 1115 Brooks Street, Shreveport, LA, 71101.
authors.forename: Monnie
authors.initials: M
authors.lastname: Michalik
authors.affiliation: Applied Testing, QIAGEN, Inc., 19300 Germantown Rd., Germantown, MD, 20874.
authors.forename: Mary Jones
authors.initials: MJ
authors.lastname: Dukes
authors.affiliation: North Louisiana Criminalistics Laboratory, 1115 Brooks Street, Shreveport, LA, 71101.
authors.forename: Patrick
authors.initials: P
authors.lastname: Wojtkiewicz
mesh_terms: D000483:Alleles; D004247:DNA / Q000032:analysis; D019075:Electrophoresis, Capillary; D053803:Forensic Genetics; D006801:Humans; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction
chemical_list: D004247:DNA
keywords: capillary electrophoresis; electrokinetic injection; forensic DNA typing; forensic science; internal lane standard; short tandem repeats