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John M Butler

Publications and source records attributed to John M Butler.

At least 19 recordsLinked to original sources
PubMed2006

Allele frequencies for 27 Y-STR loci with U.S. Caucasian, African American, and Hispanic samples.

A total of 263 U.S. Caucasians, 260 African Americans and 140 U.S. Hispanics or a subset of 31 Caucasians, 32 African Americans, and 32 Hispanics were typed for 27 Y-chromosome short tandem repeat (Y-STR) markers: DYS444, DYS446, DYS449, DYS463, DYS485, DYS490, DYS495, DYS504, DYS505, DYS508, DYS520, DYS522, DYS525, DYS532, DYS533, DYS534, DYS540, DYS556, DYS557, DYS570, DYS575, DYS576, DYS594, DYS632, DYS635, DYS641, and DYS643. Allele frequencies for each locus are reported along with nomenclature based on sequence analysis.

Chromosomes, Human, Y↗
PubMed2006

Multiplex_QA: an exploratory quality assessment tool for multiplexed electrophoretic assays.

Multiplex_QA is a data analysis tool for visualizing short- and long-term changes in the performance of multiplexed electrophoretic assays, particularly the commercial short tandem repeat (STR) kits used by the human forensic identity community. A number of quality metrics are calculated from the signal collected for the internal size standard included in nearly all multiplex assays. These quality metrics are related to the signal intensity, symmetry, retention, resolution, and noise of data collected by capillary electrophoresis systems. Interlocking graphical displays enable the identification of changes in the quality metrics with time, evaluation of relationships among the metrics, and detailed examination of electropherographic features of particularly interesting analyses. While primarily intended for exploring which metrics are most useful for documenting data quality, the current version of the tool is sufficiently robust for use by forensic scientists with an interest in data analysis and access to a fast desktop computer.

DNA↗
PubMed2006

Genetics and genomics of core short tandem repeat loci used in human identity testing.

Over the past decade, the human identity testing community has settled on a set of core short tandem repeat (STR) loci that are widely used for DNA typing applications. A variety of commercial kits enable robust amplification of these core STR loci. A brief history is presented regarding the selection of core autosomal and Y-chromosomal STR markers. The physical location of each STR locus in the human genome is delineated and allele ranges and variants observed in human populations are summarized as are mutation rates observed from parentage testing. Internet resources for additional information on core STR loci are reviewed. Additional topics are also discussed, including potential linkage of STR loci to genetic disease-causing genes, probabilistic predictions of sample ethnicity, and desirable characteristics for additional STR loci that may be added in the future to the current core loci. These core STR loci, which form the basis for DNA databases worldwide, will continue to play an important role in forensic science for many years to come.

Alleles↗
PubMed2005

Epidemiology. DNA identifications after the 9/11 World Trade Center attack.

The attack on the World Trade Center on 9/11/2001 challenged current approaches to forensic DNA typing methods. The large number of victims and the extreme thermal and physical conditions of the site necessitated special approaches to the DNA-based identification. Because of these and many additional challenges, new procedures were created or modified from routine forensic protocols. This effort facilitated the identification of 1594 of the 2749 victims. In this Policy Forum, the authors, who were were members of the World Trade Center Kinship and Data Analysis Panel, review the lessons of the attack response from the perspective of DNA forensic identification and suggest policies and procedures for future mass disasters or large-scale terrorist attacks.

DNA↗
PubMed2005

Allele frequencies for 70 autosomal SNP loci with U.S. Caucasian, African-American, and Hispanic samples.

189 samples from 3 different U.S. sample groups Caucasian (74), African American (71) and Hispanic (44) were typed for 70 autosomal genetic markers. These 70 markers are bi-allelic (C/T) short nucleotide polymorphisms (SNPs). For each sample, the 70 SNP markers were typed in 11 unique 6-plexes and a single 4-plex PCR. A total of 10 of the 210 tests (70 loci x 3 populations) for Hardy-Weinberg equilibrium indicated a statistically significant result. In order to evaluate the minimum number of SNP loci needed to distinguish all 189 samples from one another, we ranked the loci according to their levels of observed heterozygosity and p-values obtained upon testing for Hardy-Weinberg equilibrium. The top 12 loci according to these ranking criteria were tabulated along with the number of unique genotypes observed when combining subsequent SNP markers. The 12 selected SNPs possessed an observed heterozygosity of >0.45 in all three populations examined and thus would be expected to exhibit more differences between samples. All of the 189 samples in this study were individualized with a subset of 12 SNP loci. However, it is likely that the addition of more than 12 SNP loci will be required to resolve larger sets of unrelated individuals from one another. By way of comparison, in these same 189 individuals all but one pair is resolved from one another with three of the traditional short tandem repeat (STR) loci possessing the highest heterozygosity values (D2S1338, D18S51, and FGA) run with the Identifiler kit. The final pair of unrelated samples could be resolved with the combination of 4 STR loci: D2S1338, D18S51, FGA, and VWA.

DNA Fingerprinting↗
PubMed2005

Locus-specific brackets for reliable typing of Y-chromosome short tandem repeat markers.

Short tandem repeat (STR) loci, widely used as genetic markers in disease diagnostic studies and human identity applications, are traditionally genotyped through comparison of allele sizes to a sequenced allelic ladder. Allelic ladders permit a floating bin allele calling method to be utilized, which enables reliable allele calling across laboratories, instrument platforms, and electrophoretic conditions. Precise sizing methods for STR allele calling involving fixed bins can also be used when a high degree of precision has been demonstrated within an instrument platform and a set of electrophoretic conditions. An alternative method for reliable genotyping of STR markers, locus-specific brackets (LSBs), is introduced here. LSBs are artificial alleles created through molecular biology manipulations to be shorter or longer than alleles commonly seen in populations under investigation. The size and repeat number of measured alleles are interpolated between the two LSB products that are mixed with the polymerase chain reaction-amplified STR alleles. The advantages and limitations of the LSB approach are described along with a concordance study between the LSB typing approach and other STR typing methods. Complete agreement was observed with 162 samples studied at 5 Y-chromosome loci.

Alleles↗
PubMed2005

Constructing STR multiplex assays.

Multiplex polymerase chain reaction (PCR) refers to the simultaneous amplification of multiple regions of deoxyribonucleic acid (DNA) using PCR. Commercial short tandem repeat (STR) assays that can coamplify as many as 16 different loci have become widely used in forensic DNA typing. This chapter will focus on some of the aspects of constructing robust STR multiplex assays, including careful design and quality control of PCR primers. Examples from the development of a cat STR 12plex and a human Y chromosome STR 20plex are used to illustrate the importance of various parts of the protocol. Primer design parameters and Internet-accessible resources are discussed, as are solutions to problems with residual dye artifacts that result from impure primers.

Chromosomes, Human, Y↗
PubMed2005

Mitochondrial DNA typing screens with control region and coding region SNPs.

Mitochondrial DNA (mtDNA) analysis has found an important niche in forensic DNA typing. It is used with highly degraded samples or low-copy number materials such as might be found from shed hair or bones exposed to severe environmental conditions. The primary advantage of mtDNA is that it is present in high copy number within cells and therefore more likely to be recovered from highly degraded specimens. A major disadvantage to traditional forensic mtDNA analysis is that it is time-consuming and labor-intensive to generate and review the 610 nucleotides of sequence information commonly targeted in hypervariable regions I and II (HVI and HVII) of the control region. In addition, common haplotypes exist in HVI/HVII mtDNA sequences that can reduce the ability to differentiate two unrelated samples. In this report we describe the utility of two newly available screening assays for rapid exclusion of non-matching samples. The LINEAR ARRAY mtDNA HVI/HVII Region-Sequencing Typing Kit (Roche Applied Science, Indianapolis, IN) was used to type 666 individuals from U.S. Caucasian, African American, and Hispanic groups. Processing of the LINEAR ARRAY probe panels "mito strips" was automated on a ProfiBlot workstation. Observable variation in 666 individuals is reported and frequencies of the mitotypes within and between populations are presented. Samples exhibiting the most common Caucasian mitotype were subdivided with a multiplexed amplification and detection assay using eleven single nucleotide polymorphisms in the mitochondrial genome. These types of screening assays should enable more rapid evaluation of forensic casework samples such that only samples not excluded would be subjected to further characterization through full HVI/HVII mtDNA sequence analysis.

Automation↗
PubMed2005

Characterization of new miniSTR loci to aid analysis of degraded DNA.

A number of studies have demonstrated that successful analysis of degraded DNA specimens from mass disasters or forensic evidence improves with smaller sized polymerase chain reaction (PCR) products. We have scanned the literature for new STR loci, unlinked from the CODIS markers, which can generate amplicons less than 125 bp in size and would therefore be helpful in testing degraded DNA samples. New PCR primers were designed and tested for the STR loci D1S1677, D2S441, D4S2364, D10S1248, D14S1434, and D22S1045, arranged into two miniSTR triplexes. All loci show a moderate degree of polymorphism among 474 U.S. population samples tested and were reliable and sensitive to at least 100 pg of DNA template under controlled laboratory conditions and pristine DNA samples. The utility of these new loci were confirmed in comparing the success of the miniSTR assays for typing degraded bone samples while partial profiles were observed with the majority of the samples using a commercial STR kit.

Bone and Bones↗
PubMed2005

Results from the NIST 2004 DNA Quantitation Study.

For optimal DNA short tandem repeat (STR) typing results, the DNA concentration ([DNA]) of the sample must be accurately determined prior to the polymerase chain reaction (PCR) amplification step in the typing process. In early 2004, the National Institute of Standards and Technology (NIST) conducted an interlaboratory study to help assess the accuracy of DNA quantitation in forensic DNA laboratories. This study was designed with four primary purposes: (1) to examine concentration effects and to probe performance at the lower DNA concentration levels that are frequently seen in forensic casework; (2) to examine consistency with various methodologies across multiple laboratories; (3) to examine single versus multiple source samples; and (4) to study DNA stability over time and through shipping in two types of storage tubes. Eight DNA samples of [DNA] from 0.05 ng/microL to 1.5 ng/microL were distributed. A total of 287 independent data sets were returned from 80 participants. Results were reported for 19 different DNA quantitation methodologies. Approximately 65% of the data were obtained using traditional slot blot hybridization methods; 21% were obtained using newly available quantitative real-time PCR (Q-PCR) techniques. Information from this interlaboratory study is guiding development of a future NIST Standard Reference Material for Human DNA Quantitation, SRM 2372.

DNA↗
PubMed2005

Chromosomal duplications along the Y-chromosome and their potential impact on Y-STR interpretation.

Y-chromosome short tandem repeat (Y-STR) markers are being used as potential tools for distinguishing low levels of male DNA in the presence of excess female DNA as is present in many sexual assault samples. Usually single copy Y-STR loci produce a single amplicon in single source samples, and thus the observation of multiple peaks at such a locus could suggest to an analyst that a mixture of more than one male contributor is present in the tested sample. However, many regions of the Y-chromosome are duplicated or even triplicated in some individuals and this fact can thus complicate potential mixture interpretation. Reasons for the presence of duplications at multiple loci within a single sample are explored in the context of Y-STR marker location along the chromosome. True male-male mixtures commonly exhibit more than one locus-specific PCR product across multiple Y-STR loci that are not adjacent to one another on the Y-chromosome. In addition, duplicated loci typically possess alleles that differ by only a single repeat unit and possess similar peak heights.

Alleles↗
PubMed2005

An STR forensic typing system for genetic individualization of domestic cat (Felis catus) samples.

A forensic genotyping panel of 11 tetranucleotide STR loci from the domestic cat was characterized and evaluated for genetic individualization of cat tissues. We first examined 49 candidate STR loci and their frequency assessment in domestic cat populations. The STR loci (3-4 base pair repeat motifs), mapped in the cat genome relative to 579 coding loci and 255 STR loci, are well distributed across the 18 feline autosomes. All loci exhibit Mendelian inheritance in a multi-generation pedigree. Eleven loci that were unlinked and were highly heterozygous in cat breeds were selected for a forensic panel. Heterozygosity values obtained for the independent loci, ranged from 0.60-0.82, while the average cat breed heterozygosity obtained for the 11 locus panel was 0.71 (range of 0.57-0.83). A small sample set of outbred domestic cats displayed a heterozygosity of 0.86 for the 11 locus panel. The power of discrimination of the panel is moderate to high in the cat breeds examined, with an average P(m) of 3.7E-06. The panel shows good potential for genetic individualization within outbred domestic cats with a P(m) of 5.31E-08. A multiplex protocol, designed for the co-amplification of the 11 loci and a gender-identifying locus, is species specific and robust, generating a product profile with as little as 0.125 nanograms of genomic DNA.

Animals↗
PubMed2004

Toward increased utility of mtDNA in forensic identifications.

The utility of mtDNA in forensic identifications is limited by its low power of discrimination and the absence of high quality mtDNA databases. Single nucleotide polymorphisms (SNPs) in the control region outside of hypervariable regions I and II (HVI/HVII), and in the coding region of the mtDNA genome, can provide additional discrimination in mtDNA testing. We have identified particularly useful SNP sites via high throughput sequencing of the entire mtDNA genome. We report here two cases in which an 11-plex SNP assay (panel "A") targeting the most common HVI/HVII type successfully resolved two cases in which identifications could not be made on the basis of HVI/HVII sequencing. Additionally, we established a database of 286 samples for SNP panel "A" generated with robotic protocols. We have addressed the need for high quality mtDNA control region (CR) databases by developing robotic protocols for lab processing, and a carefully devised electronic data review process. A large-scale databasing effort targeting several populations underrepresented in current mtDNA databases is underway.

Complementarity Determining Regions↗
PubMed2004

NIST mixed stain study 3: signal intensity balance in commercial short tandem repeat multiplexes.

Short-tandem repeat (STR) allelic intensities were collected from more than 60 forensic laboratories for a suite of seven samples as part of the National Institute of Standards and Technology-coordinated 2001 Mixed Stain Study 3 (MSS3). These interlaboratory challenge data illuminate the relative importance of intrinsic and user-determined factors affecting the locus-to-locus balance of signal intensities for currently used STR multiplexes. To varying degrees, seven of the eight commercially produced multiplexes used by MSS3 participants displayed very similar patterns of intensity differences among the different loci probed by the multiplexes for all samples, in the hands of multiple analysts, with a variety of supplies and instruments. These systematic differences reflect intrinsic properties of the individual multiplexes, not user-controllable measurement practices. To the extent that quality systems specify minimum and maximum absolute intensities for data acceptability and data interpretation schema require among-locus balance, these intrinsic intensity differences may decrease the utility of multiplex results and surely increase the cost of analysis.

Alleles↗
PubMed2004

Duplication of DYS19 flanking regions in other parts of the Y chromosome.

During the testing of alternative primers for the Y chromosome short tandem repeat marker DYS19, a duplicated region of the Y chromosome was discovered. The duplicated sequence is contained within GenBank accession AC006335 and has a high degree of homology with the DYS19 flanking region (GenBank accession AC017019) but without the polymorphic TAGA repeat. Bioinformatic approaches have been taken to try and understand the implications of this homolog to enable improved primer design for DYS19. Sequence alignments and careful placement of primers in order to obtain specific amplification of the DYS19 locus are discussed in the context of all previously published primer sets. Since the DYS19 locus is part of the widely used minimal haplotype, its robust amplification is highly desirable particularly in multiplex reactions. The discovery of this duplicated region of the Y chromosome shows the value of newly available human genome sequence information for assay design and the importance of using sequence queries and alignments in the primer design process.

5' Flanking Region↗
PubMed2004

A multiplex allele-specific primer extension assay for forensically informative SNPs distributed throughout the mitochondrial genome.

The typing of single nucleotide polymorphisms (SNPs) located throughout the mitochondrial genome (mtGenome) can help resolve individuals with an identical HV1/HV2 mitotype. A set of 11 SNPs selected for distinguishing individuals of the most common Caucasian HV1/HV2 mitotype were incorporated in an allele specific primer extension assay. The assay was optimized for multiplex detection of SNPs at positions 3010, 4793, 10211, 5004, 7028, 7202, 16519, 12858, 4580, 477 and 14470 in the mtGenome. Primers were designed to allow for simultaneous PCR amplification of 11 unique regions in the mtGenome and subsequent primer extension. By enzymatically incorporating fluorescently labeled dideoxynucleotides (ddNTPs) onto the 3' end of the extension primer, detection can be accomplished with a capillary-based electrophoresis (CE) platform common in most forensic laboratories. The electrophoretic mobility for the extension primers was compared in denaturing POP4 and POP6 CE running buffers. Empirical adjustment of extension primer concentrations resulted in even signal intensity for the 11 loci probed. We demonstrate that the assay performs well for heteroplasmy and mixture detection, and for typical mtDNA casework samples with highly degraded DNA.

Alleles↗