TWGDAM validation of AmpFlSTR PCR amplification kits for forensic DNA casework

Laboratory procedures used in short tandem repeat (STR) analysis were subjected to various scenarios that assessed reliability and identified potential limitations. These validation studies were designed as recommended by the Technical Working Group on DNA Analysis Methods (TWGDAM) and the DNA Advisory Board (DAB) (17,18). Various DNA samples were amplified by the polymerase chain reaction (PCR) using AmpFlSTR PCR Amplification Kits (i.e., AmpFlSTR Green I, Profiler, Profiler Plus, and COfiler kits), detected with ABI Prism instrumentation, and analyzed using GeneScan and Genotyper software. Data acquired in these studies reinforced an existing body of knowledge and expertise regarding application and interpretation of STR typing in the forensic science community. Consistent STR genotypes were detected in various body tissues and fluids. Inter-laboratory comparisons produced concordant genotype results. Quantitative interpretational aids for DNA mixtures were characterized. Ability of the typing systems to type potentially compromised samples reliably was evaluated. Nonprobative case evidentiary DNA was successfully amplified, genotyped, and interpreted. Potential limitations or cautionary factors in the interpretation of minimal fluorescence intensity were demonstrated. Differential amplification between loci was observed when PCR was inhibited; preferential amplification typically was not. Single AmpFlSTR locus amplification did not offer consistent benefit over AmpFlSTR multiplexing, even in cases of DNA degradation or PCR inhibition. During rigorous evaluation, AmpFlSTR PCR Amplification Kits reproducibly yielded sensitive and locus-specific results, as required in routine forensic analyses.     

AmpFlSTR Profiler Plus and AmpFlSTR COfiler analysis of tissues stored in GenoFix, a new tissue preservation solution for mass disaster DNA identification

A preliminary study was conducted to assess the capability of a new alcohol-based tissue fixative, GenoFix, to preserve DNA from biopsy tissues stored at room temperature and/or -20 degrees C in a freezer, for subsequent short tandem repeat (STR) DNA typing analysis. Fresh human smooth muscle samples were stored at room temperature in GenoFix for one month and up to one year and seven months before being processed using the megaplex STR systems, AmpFlSTR Profiler Plus and AmpFlSTR COfiler. Alternatively, muscle tissues in GenoFix were placed at -20 degrees C in a freezer for up to 3 1/2 years following two to three months in the fixative at room temperature. DNA analysis was also carried out on tissues stored in GenoFix for one month at room temperature and subsequently paraffin-embedded and stored at room temperature for four years. The AmpFlSTR Profiler Plus and AmpFlSTR COfiler STR profiles produced, using DNA extracted from all fixed tissue samples, were of very good quality. The fluorescent signals were well balanced across the nine STR loci or six loci comprised in the megaplexes surveyed and profiles showed no differences with those observed for the control blood of the respective donor patients. Continuous exposure to GenoFix at room temperature (up to one year and seven months) did not compromise the STR typing analysis of the fixed tissues. No adverse effects were noted on the STR typeability of tissues fixed with GenoFix and stored at -20 degrees C in a freezer for up to 3 1/2 years. STR profiles generated from the paraffin-embedded tissues fixed in GenoFix were of excellent quality. This preliminary study suggests that GenoFix can be used to store tissue samples at room temperature for up to one year and seven months or at -20 degrees C in a freezer for longer storage (up to 3 1/2 years). This new and odorless tissue fixative promotes tissue and DNA preservation in a very effective manner and as such may prove useful in criminal investigations or mass disaster identifications carried out in remote locations and in which a small or large number of tissue samples are collected for further analyses.     

Allele frequencies for nine STR loci in Ovambo population using AmpFlSTR Profiler Kit

Allele frequencies for the nine short tandem repeat (STR) loci D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S820 were investigated in 195 unrelated Ovambo (Bantus) population from Namibia. AmpFlSTR Profiler Kit was employed for amplification. For each locus, 6-19 alleles were observed. Comparison between Ovambo population data and that of other African populations was performed. AmpFlSTR Profiler detection system is a useful tool for individual identification in Ovambo population.     

Fast PCR amplification of AmpFlSTR Identifiler

To increase throughput for DNA typing, we examined fast PCR cycling using AmpFlSTR Identifiler by three methods. In this study, we reduced PCR running times by 1/3 to 2/3 (approximately 1-2 h). This means DNA typing, including PCR reactions, can be completed within a timeframe ranging from 90 min to 2 h and 30 min.     

Fast PCR amplification using AmpFlSTR Identifiler: Second report

At ISFG2007, an earlier conference, we presented reports on two fast PCR cycling methods using AmpFlSTR Identifiler. In our current study, which involved PCR amplification using AmpliTaq Gold Fast PCR Master Mix, UP, and a standard PCR thermal cycler rather than the Fast PCR thermal cycler, we succeeded in allele typing while reducing PCR running times by half (to approximately 90 min).     

TWGDAM validation of the AmpFlSTR Profiler Plus and AmpFlSTR COfiler STR multiplex systems using capillary electrophoresis

Prior to forensic implementation, a profiling system requires validation following the recommendations presented by the Technical Working Group on DNA Analysis Methods (TWGDAM). In this work two such systems, AmpFlSTR Profiler Plus and AmpFfSTR COfiler have been validated according to the guidelines provided by TWGDAM. Profiler Plus and COfiler simultaneously amplify nine and six STR loci respectively; both also amplify a portion of the amelogenin gene. Performance of the two STR multiplex systems under conditions set forth by TWGDAM was robust and reproducible, indicating that these systems are suitable for use in forensic analysis. Additionally, specific sections of the TWGDAM validation guidelines are especially valuable in terms of familiarizing users with particular limitations of the systems prior to taking on casework.     

STR data for the 15 AmpFlSTR identifiler loci in the Western Romanian population

Allele frequencies for the 15 tetranucleotide short tandem repeat loci contained in the AmpFlSTR Identifiler kit were obtained from a population sample of 219 unrelated individuals born in the western part of Romania.     

STR data for the AmpFlSTR Profiler Plus loci from Greece

Allele frequencies for the nine STRs included in the AmpFlSTR Profiler Plus kit (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) were estimated from a sample of 143 unrelated individuals living in different regions of Greece.     

STR data (AmpFlSTR profiler plus) from north Portugal

Allele frequencies for the nine STRs included in the AmpFlSTR Profiler Plus kit (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) were estimated from a sample of 365-427 unrelated individuals born in north Portugal.     

Brazilian population database for the 13 STR loci of the AmpFlSTR Profiler Plus and Cofiler multiplex kits

Allele frequencies for the 13 STR core loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, CSF1PO, TPOX, THO1 and D16S539) included in the AmpFlSTR((R)) Profiler Plus and AmpFlSTR((R)) Cofiler kits were obtained for a sample of 700-800 genetically unrelated Brazilians. The expected performance of these loci for personal identification and paternity testing in the Brazilian population was estimated.     

STR data for the AmpFlSTR Profiler Plus loci from Murcia region (SE Spain)

Frequency data of the nine STRs included in the AmpFlSTR Profiler Plus Kit were determined in a sample of 114 unrelated individuals from Murcia region (SE Spain).     

Japanese population database for nine STR loci of the AmpFlSTR Profiler kit

Allele frequencies for nine short tandem repeats (STR) loci: D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317 and D7S820 were determined in a Japanese population using the AmpFlSTR Profiler PCR amplification kit (Applied biosystems).     

Typeability of AmpFlSTR SGM Plus loci in brain and thyroid gland tissue samples incubated in different environments

Autolysis and putrefaction are crucial factors responsible for degradation of cells, tissues, and organs. Postmortem changes may assume different course depending on extrinsic and intrinsic conditions. The aim of the study was assessment of environmental effect on typeability of AmpFlSTR SGM Plus loci: D3S1358, VWA, D16S539, D2S1338, D81179, D21S11, D18S51, D19S433, TH01, FGA, and gender marker amelogenin. Brain and thyroid gland tissue specimens collected during autopsies of five persons aged 20-30 years were incubated at 21 degrees C and 4 degrees C in different environmental conditions. DNA was extracted by organic method from tissue samples collected in 7-day intervals and subsequently typed using AmpFlSTR SGM Plus kit and ABI 310. A fast decrease in typeability rate was seen in specimens incubated in peat soil and in sand. Brain tissue samples were typeable in all AmpFlSTR SGM Plus loci within 126 days of incubation at 4 degrees C. Faster DNA degradation was recorded in thyroid gland specimens. In samples with negative genotyping results, no DNA was found by fluorometric quantitiation.     

STR data for the AmpFlSTR SGM Plus loci from Shantou (south of China)

Allele frequencies for the ten STRs included in the AmpFlSTR SGM Plus kit were obtained from a sample of 132 unrelated Han individuals born in the region of Shantou (south of China).     

Portuguese population and paternity investigation studies with a multiplex PCR--the AmpFlSTR Profiler Plus

A Portuguese Caucasian population of 146 unrelated individuals was studied. DNA samples were amplified by multiplex PCR for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 using the AmpFlSTR Profiler Plus PCR Amplification Kit (Perkin-Elmer). All loci met Hardy-Weinberg expectations. Forensic statistical parameters were according to those obtained by other authors. Statistical differences were observed concerning three loci when comparing the Portuguese Caucasian population and an Italian Caucasian population, although these differences mainly concern the less frequent alleles. Eighty-three paternity investigation cases were analysed. Exclusions in between three and nine loci were observed in all the 23 exclusion cases obtained. Most of the non-exclusion cases had probability of paternity > 99.9%. Two cases with an isolated genetic incompatibility between the alleged father and the child were detected, which may indicate probable mutation cases. These results demonstrate that the AmpFlSTR Profiler Plus is a suitable multiplex for paternity investigation in the Portuguese population.     

STR data for the AmpFlSTR SGM Plus from Aegean region of Turkey

Allele frequencies of the 10 STRs loci (D16S539, D2S1338, D3S1358, vWA, D18S51, D21S11, D8S1179, D19S433, FGA, THO1) included in the AmpFlSTR SGM Plus Kit (PE Applied Biosystems) were obtained from a sample of 166 unrelated individuals in Aegean region of Turkey.     

STR data (AmpFlSTR Profiler Plus and GenePrint CTTv) from Mozambique

Allele frequencies for twelve STRs included in the AmpFlSTR Profiler Plus kit (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) and GenePrint CTTv kit (VWA, TH01, TPO and CSF1PO) were estimated from a sample of 110 unrelated individuals from Mozambique.     

STR data for the AmpFlSTR profiler plus loci from Macau (China).

Allele frequencies for the nine STRs included in the AmpFlSTR profiler plus kit (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820) were estimated from a sample of 87 unrelated individuals living in the region of Macau, a territory located in the southeastern coast of China.     

STR data for the AmpFlSTR SGM Plus from Marmara region of Turkey

Allele frequencies of the 10 STRs loci (D16S539, D2S1338, D3S1358, vWA, D18S51, D21S11, D8S1179, D19S433, FGA, THO1) included in the AmpFlSTR SGM Plus kit (PE Applied Biosystems) were obtained from a sample of 173 unrelated individuals in Marmara region of Turkey.     

STR data for the AmpFlSTR profiler plus loci from Majorcan, Minorcan and Valencian populations (Eastern Spain)

Frequency data of the nine STRs included in the AmpFlSTR profiler plus kit were determined in a sample of 304 unrelated individuals from three Spanish populations: 103 from Majorca, 100 from Minorca, and 101 from Valencia.