| 1. |
- Andreaggi, Kimberly, et al.
(författare)
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Complete Mitochondrial DNA Genome Variation in the Swedish Population
- 2023
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 14:11, s. 1989-1989
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Tidskriftsartikel (refereegranskat)abstract
- The development of complete mitochondrial genome (mitogenome) reference data for inclusion in publicly available population databases is currently underway, and the generation of more high-quality mitogenomes will only enhance the statistical power of this forensically useful locus. To characterize mitogenome variation in Sweden, the mitochondrial DNA (mtDNA) reads from the SweGen whole genome sequencing (WGS) dataset were analyzed. To overcome the interference from low-frequency nuclear mtDNA segments (NUMTs), a 10% variant frequency threshold was applied for the analysis. In total, 934 forensic-quality mitogenome haplotypes were characterized. Almost 45% of the SweGen haplotypes belonged to haplogroup H. Nearly all mitogenome haplotypes (99.1%) were assigned to European haplogroups, which was expected based on previous mtDNA studies of the Swedish population. There were signature northern Swedish and Finnish haplogroups observed in the dataset (e.g., U5b1, W1a), consistent with the nuclear DNA analyses of the SweGen data. The complete mitogenome analysis resulted in high haplotype diversity (0.9996) with a random match probability of 0.15%. Overall, the SweGen mitogenomes provide a large mtDNA reference dataset for the Swedish population and also contribute to the effort to estimate global mitogenome haplotype frequencies.
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| 2. |
- Ballantyne, Kaye N., et al.
(författare)
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Toward Male Individualization with Rapidly Mutating Y-Chromosomal Short Tandem Repeats
- 2014
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Ingår i: Human Mutation. - : John Wiley & Sons. - 1059-7794 .- 1098-1004. ; 35:8, s. 1021-1032
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Tidskriftsartikel (refereegranskat)abstract
- Relevant for various areas of human genetics, Y-chromosomal short tandem repeats (Y-STRs) are commonly used for testing close paternal relationships among individuals and populations, and for male lineage identification. However, even the widely used 17-loci Yfiler set cannot resolve individuals and populations completely. Here, 52 centers generated quality-controlled data of 13 rapidly mutating (RM) Y-STRs in 14,644 related and unrelated males from 111 worldwide populations. Strikingly, greater than99% of the 12,272 unrelated males were completely individualized. Haplotype diversity was extremely high (global: 0.9999985, regional: 0.99836-0.9999988). Haplotype sharing between populations was almost absent except for six (0.05%) of the 12,156 haplotypes. Haplotype sharing within populations was generally rare (0.8% nonunique haplotypes), significantly lower in urban (0.9%) than rural (2.1%) and highest in endogamous groups (14.3%). Analysis of molecular variance revealed 99.98% of variation within populations, 0.018% among populations within groups, and 0.002% among groups. Of the 2,372 newly and 156 previously typed male relative pairs, 29% were differentiated including 27% of the 2,378 father-son pairs. Relative to Yfiler, haplotype diversity was increased in 86% of the populations tested and overall male relative differentiation was raised by 23.5%. Our study demonstrates the value of RMY-STRs in identifying and separating unrelated and related males and provides a reference database.
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| 3. |
- Bus, Magdalena M., et al.
(författare)
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Mitochondrial DNA analysis of a Viking age mass grave in Sweden
- 2019
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Ingår i: Forensic Science International. - : Elsevier BV. - 1872-4973 .- 1878-0326. ; 42, s. 268-274
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Tidskriftsartikel (refereegranskat)abstract
- In 1998, a Viking Age mass grave was discovered and excavated at St. Laurence's churchyard in Sigtuna, Sweden. The excavated bones underwent osteoarchaeological analysis and were assigned to at least 19 individuals. Eleven skeletons showed sharp force trauma from bladed weapons. Mass graves are an unusual finding from this time period, making the burial context extraordinary. To investigate a possible maternal kinship among the individuals, bones and teeth from the skeletal remains were selected for mitochondrial DNA (mtDNA) analysis. Sanger sequencing of short stretches of the hypervariable segments I and II (HVS-I and HVS-II) was performed. A subset of the samples was also analysed by massively parallel sequencing analysis (MPS) of the entire mtDNA genome using the Precision ID mtDNA Whole Genome Panel. A total of 15 unique and three shared mtDNA profiles were obtained. Based on a combination of genetic and archaeological data, we conclude that a minimum of 20 individuals was buried in the mass grave. The majority of the individuals were not maternally related. However, two possible pairs of siblings or mother-child relationships were identified. All individuals were assigned to West Eurasian haplogroups, with a predominance of haplogroup H. Although the remains showed an advanced level of DNA degradation, the combined use of Sanger sequencing and MPS with the Precision ID mtDNA Whole Genome Panel revealed at least partial mtDNA data for all samples.
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| 4. |
- Chaitanya, Lakshmi, et al.
(författare)
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Collaborative EDNAP exercise on the IrisPlex system for DNA based prediction of human eye colour
- 2014
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Ingår i: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 11, s. 241-251
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Tidskriftsartikel (refereegranskat)abstract
- The IrisPlex system is a DNA-based test system for the prediction of human eye colour from biological samples and consists of a single forensically validated multiplex genotyping assay together with a statistical prediction model that is based on genotypes and phenotypes from thousands of individuals. IrisPlex predicts blue and brown human eye colour with, on average, >94% precision accuracy using six of the currently most eye colour informative single nucleotide polymorphisms (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, SLC45A2 (MATP) rs16891982, TYR rs1393350, and IRF4 rs12203592) according to a previous study, while the accuracy in predicting non-blue and non-brown eye colours is considerably lower. In an effort to vigorously assess the IrisPlex system at the international level, testing was performed by 21 laboratories in the context of a collaborative exercise divided into three tasks and organised by the European DNA Profiling (EDNAP) Group of the International Society of Forensic Genetics (ISFG). Task 1 involved the assessment of 10 blood and saliva samples provided on FTA cards by the organising laboratory together with eye colour phenotypes; 99.4% of the genotypes were correctly reported and 99% of the eye colour phenotypes were correctly predicted. Task 2 involved the assessment of 5 DNA samples extracted by the host laboratory from simulated casework samples, artificially degraded, and provided to the participants in varying DNA concentrations. For this task, 98.7% of the genotypes were correctly determined and 96.2% of eye colour phenotypes were correctly inferred. For Tasks 1 and 2 together, 99.2% (1875) of the 1890 genotypes were correctly generated and of the 15 (0.8%) incorrect genotype calls, only 2 (0.1%) resulted in incorrect eye colour phenotypes. The voluntary Task 3 involved participants choosing their own test subjects for IrisPlex genotyping and eye colour phenotype inference, while eye photographs were provided to the organising laboratory and judged; 96% of the eye colour phenotypes were inferred correctly across 100 samples and 19 laboratories. The high success rates in genotyping and eye colour phenotyping clearly demonstrate the reproducibility and the robustness of the IrisPlex assay as well as the accuracy of the IrisPlex model to predict blue and brown eye colour from DNA. Additionally, this study demonstrates the ease with which the IrisPlex system is implementable and applicable across forensic laboratories around the world with varying pre-existing experiences.
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| 5. |
- Daskalaki, Evangelia
(författare)
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Archaeological Genetics - Approaching Human History through DNA Analysis
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There are a variety of archaeological questions, which are difficult to assess by traditional archaeological methods. Similarly, there are genetic and population genetic questions about human evolution and migration that are difficult to assess by studying modern day genetic variation. Archaeological genetics can directly study the archaeological remains, allowing human history to be explored by means of genetics, and genetics to be expanded into historical and pre-historical times. Examples of archaeological questions that can be resolved by genetics are determining biological sex on archaeological remains and exploring the kinship or groups buried in close proximity. Another example is one of the most important events in human prehistory – the transition from a hunter-gatherer lifestyle to farming - was driven through the diffusion of ideas or with migrating farmers. Molecular genetics has the potential to contribute in answering all these questions as well as others of similar nature. However, it is essential that the pitfalls of ancient DNA, namely fragmentation, damage and contamination are handled during data collection and data analysis.Analyses of ancient DNA presented in this thesis are based on both mitochondrial DNA and nuclear DNA through the study of single nuclear polymorphisms (SNPs). I used pyrosequencing assays in order to identify the biological sex of archaeological remains as well as verifying if fragmented remains were human or from animal sources. I used a clonal assay approach in order to retrieve sequences for the HVRI of a small family-like burial constellation from the Viking age. By the use of low coverage shotgun sequencing I retrieved sequence data from 13 crew members from the 17th century Swedish man-of-war Kronan. This data was used to determine the ancestry of the crew, which in some cases was speculated to be of non-Scandinavian or non-European origin. However, I demonstrate that all individuals were of European ancestry. Finally, I retrieved sequence data from a Neolithic farmer from the Iberian Peninsula, which added one more facet of information in exploring the Neolithization process of Europe. The Neolithic Iberian individual was genetically similar to Scandinavian Neolithic farmers, indicating that the genetic variation of prehistoric Europe correlated with subsistence mode rather than with geography.
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| 6. |
- Marshall, Charla, et al.
(författare)
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Pathogenic Variant Filtering for Mitochondrial Genome Haplotype Reporting
- 2020
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Ingår i: Genes. - : MDPI. - 2073-4425. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Given the enhanced discriminatory power of the mitochondrial DNA (mtDNA) genome (mitogenome) over the commonly sequenced control region (CR) portion, the scientific merit of mitogenome sequencing is generally accepted. However, many laboratories remain beholden to CR sequencing due to privacy policies and legal requirements restricting the use of disease information or coding region (codR) information. In this report, we present an approach to obviate the reporting of sensitive codR data in forensic haplotypes. We consulted the MitoMap database to identify 92 mtDNA codR variants with confirmed pathogenicity. We determined the frequencies of these pathogenic variants in literature-quality and forensic-quality databases to be very low, at 1.2% and 0.36%, respectively. The observed effect of pathogenic variant filtering on random match statistics in 2488 forensic-quality mitogenome haplotypes from four populations was nil. We propose that pathogenic variant filtering should be incorporated into variant calling algorithms for mitogenome haplotype reporting to maximize the discriminatory power of the locus while minimizing the reveal of sensitive genetic information.
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| 7. |
- Müller, Petra, et al.
(författare)
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Inter-laboratory study on standardized MPS libraries : evaluation of performance, concordance, and sensitivity using mixtures and degraded DNA
- 2020
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Ingår i: International Journal of Legal Medicine. - : Springer Science and Business Media LLC. - 0937-9827 .- 1437-1596. ; 134:1, s. 185-198
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Tidskriftsartikel (refereegranskat)abstract
- We present results from an inter-laboratory massively parallel sequencing (MPS) study in the framework of the SeqForSTRs project to evaluate forensically relevant parameters, such as performance, concordance, and sensitivity, using a standardized sequencing library including reference material, mixtures, and ancient DNA samples. The standardized library was prepared using the ForenSeq DNA Signature Prep Kit (primer mix A). The library was shared between eight European laboratories located in Austria, France, Germany, The Netherlands, and Sweden to perform MPS on their particular MiSeq FGx sequencers. Despite variation in performance between sequencing runs, all laboratories obtained quality metrics that fell within the manufacturer’s recommended ranges. Furthermore, differences in locus coverage did not inevitably adversely affect heterozygous balance. Inter-laboratory concordance showed 100% concordant genotypes for the included autosomal and Y-STRs, and still, X-STR concordance exceeded 83%. The exclusive reasons for X-STR discordances were drop-outs at DXS10103. Sensitivity experiments demonstrated that correct allele calling varied between sequencing instruments in particular for lower DNA amounts (≤ 125 pg). The analysis of compromised DNA samples showed the drop-out of one sample (FA10013B01A) while for the remaining three degraded DNA samples MPS was able to successfully type ≥ 87% of all aSTRs, ≥ 78% of all Y-STRs, ≥ 68% of all X-STRs, and ≥ 92% of all iSNPs demonstrating that MPS is a promising tool for human identity testing, which in return, has to undergo rigorous in-house validation before it can be implemented into forensic routine casework.
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| 8. |
- Papousek, Ilona, et al.
(författare)
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Serotonin Transporter Genotype (5-HTTLPR) and Electrocortical Responses Indicating the Sensitivity to Negative Emotional Cues
- 2013
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Ingår i: Emotion. - : AMER PSYCHOLOGICAL ASSOC. - 1528-3542 .- 1931-1516. ; 13:6, s. 1173-1181
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Tidskriftsartikel (refereegranskat)abstract
- Growing literature indicates that emotional reactivity and regulation are strongly linked to genetic modulation of serotonergic neurotransmission. However, until now, most studies have focused on the relationship between genotypic markers, in particular the serotonin transporter-linked polymorphic region (5-HTTLPR), and neural structures using MRI. The current study aimed to bridge the gap between the relevant MRI literature on the effects of the 5-HTTLPR genotype and the research tradition focusing on transient lateralized changes of electrocortical activity in the prefrontal cortex using electroencephalography (EEG). Lateral shifts of EEG alpha asymmetry in response to an aversive film consisting of scenes of real injury and death were assessed in healthy participants (n = 165). To evaluate the specificity of the 5-HTTLPR effect, participants were also tested for the COMT Val158Met polymorphism which is linked to dopamine inactivation. While viewing the film, individuals homozygous for the 5-HTTLPR short allele displayed a clear lateral shift of dorsolateral frontal activity to the right, which was virtually absent in participants carrying the long allele. The heightened electrocortical response to the aversive stimulation and its direction indicates a greater propensity of s/s homozygotes to experience withdrawal oriented affect in response to negative emotion cues in the environment. Moreover, together with previous research the findings support the notion of a link between the serotonergic system and self-regulation related to avoidance motivation, and a link between the dopaminergic system and self-regulation related to approach motivation.
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| 9. |
- Strobl, Christina, et al.
(författare)
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Evaluation of the precision ID whole MtDNA genome panel for forensic analyses
- 2018
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Ingår i: Forensic Science International. - : Elsevier BV. - 1872-4973 .- 1878-0326. ; 35, s. 21-25
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial DNA (mtDNA) amplification and Massively Parallel Sequencing (MPS) using an early access version of the Precision ID Whole MtDNA Genome Panel (Thermo Fisher Scientific) and the Ion Personal Genome Machine (PGM) were evaluated using 15 forensically relevant samples. Samples were selected to represent typical forensic specimens for mtDNA analysis including hairs, hair shafts, swabs and ancient solid tissue samples (bones and teeth) that were stored in the freezer for up to several years after having been typed with conventional Sanger-type Sequencing and Capillary Electrophoresis. The MPS haplotypes confirmed the earlier results in all samples and provided additional sequence information that improved discrimination power and haplogroup estimation. The results raised the appetite for further experiments to validate and apply the new technology in forensic practice.
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| 10. |
- Sturk-Andreaggi, Kimberly, et al.
(författare)
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Impact of the sequencing method on the detection and interpretation of mitochondrial DNA length heteroplasmy
- 2020
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Ingår i: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 44
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Tidskriftsartikel (refereegranskat)abstract
- Advancements in sequencing technologies allow for rapid and efficient analysis of mitochondrial DNA (mtDNA) in forensic laboratories, which is particularly beneficial for specimens with limited nuclear DNA. Next generation sequencing (NGS) offers higher throughput and sensitivity over traditional Sanger-type sequencing (STS) as well as the ability to quantitatively analyze the data. Changes in sample preparation, sequencing method and analysis required for NGS may alter the mtDNA haplotypes compared to previously generated STS data. Thus, the present study aimed to characterize the impact of different sequencing workflows on the detection and interpretation of length heteroplasmy (LHP), a particularly complicated aspect of mtDNA analysis. Whole mtDNA genome (mitogenome) data were generated for 16 high-quality samples using well-established Illumina and Ion methods, and the NGS data were compared to previously-generated STS mtDNA control region data. Although the mitogenome haplotypes were concordant with the exception of length and low-level variants ( < 30 % variant frequency), LHP in the hypervariable segment (HVS) polycytosine regions (C-tracts) differed across sequencing methods. Consistent with previous studies, LHP in HVS1 was observed in samples with nine or more consecutive cytosines (Cs) and eight Cs in the HVS2 region in the STS data. The Illumina data produced a similar pattern of LHP as the STS data, whereas the Ion data were noticeably different. More complex LHP (i.e. more length molecules) was observed in the Ion data, as length variation occurred in multiple homopolymer stretches within the targeted HVS regions. Further, the STS dominant or major molecule (MM) differed from the Ion MM in 11 (37 %) of the 30 regions evaluated and six instances (20 %) in Illumina data. This is of particular interest, as the MM is used by many forensic laboratories to report the HVS C-tract in the mtDNA haplotype. In general, the STS MMs were longer than the Illumina MMs, while the Ion MMs were the shortest. The higher rate of homopolymer indels in Ion data likely contributed to these differences. Supplemental analysis with alternative approaches demonstrated that the LHP pattern may also be altered by the bioinformatic tool and workflow used for data interpretation. The broader application of NGS in forensic laboratories will undoubtedly result in the use of varying sample preparation and sequencing methods. Based on these findings, minor LHP differences are expected across sequencing workflows, and it will be important that C-tract indels continue to be ignored for forensic queries and comparisons.
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| 11. |
- Sturk-Andreaggi, Kimberly, 1981-, et al.
(författare)
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Mitochondrial DNA genome variation in the Swedish population
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The development of mitochondrial genome (mitogenome) reference data for inclusion in publicly-available population databases is currently underway, and the more high-quality mitogenomes that can be generated will only enhance the statistical power of this forensically-useful locus. In order to promote mitogenome testing in Sweden, the mitochondrial DNA (mtDNA) data from the SweGen whole genome sequencing (WGS) dataset were analysed. To avoid the interference from nuclear mtDNA segments (NUMTs), a 10% frequency threshold was applied for the population analyses. In total, 934 forensic-quality mitogenome haplotypes were produced. Despite the elevated frequency threshold, 31 NUMT variants were observed in 13 lower coverage haplotypes. However, NUMT interference was minimal and localized to two hotspot regions, substantially reducing the analysis burden required at lower frequency thresholds. Almost 45% of the SweGen haplotypes belonged to haplogroup H and nearly all mitogenome haplotypes (99.1%) assigned to European haplogroups, which was expected based on previous mtDNA studies of the Swedish population. There were characteristic northern Swedish (i.e., Saami) and Finnish haplogroups observe in the dataset, consistent with the nuclear DNA analyses of the SweGen data. The analysis of the complete mitogenome resulted in high haplotype diversity (0.9996) with a random match probability of 0.15%. Overall, the mitogenomes generated from the SweGen WGS data provide a mitogenome reference database for Sweden as well as contribute to the global effort to increase the availability of mitogenome reference data.
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| 12. |
- Sturk-Andreaggi, Kimberly, et al.
(författare)
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The Value of Whole-Genome Sequencing for Mitochondrial DNA Population Studies : Strategies and Criteria for Extracting High-Quality Mitogenome Haplotypes
- 2022
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- Whole-genome sequencing (WGS) data present a readily available resource for mitochondrial genome (mitogenome) haplotypes that can be utilized for genetics research including population studies. However, the reconstruction of the mitogenome is complicated by nuclear mitochondrial DNA (mtDNA) segments (NUMTs) that co-align with the mtDNA sequences and mimic authentic heteroplasmy. Two minimum variant detection thresholds, 5% and 10%, were assessed for the ability to produce authentic mitogenome haplotypes from a previously generated WGS dataset. Variants associated with NUMTs were detected in the mtDNA alignments for 91 of 917 (~8%) Swedish samples when the 5% frequency threshold was applied. The 413 observed NUMT variants were predominantly detected in two regions (nps 12,612–13,105 and 16,390–16,527), which were consistent with previously documented NUMTs. The number of NUMT variants was reduced by ~97% (400) using a 10% frequency threshold. Furthermore, the 5% frequency data were inconsistent with a platinum-quality mitogenome dataset with respect to observed heteroplasmy. These analyses illustrate that a 10% variant detection threshold may be necessary to ensure the generation of reliable mitogenome haplotypes from WGS data resources.
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| 13. |
- Sturk-Andreaggi, Kimberly, 1981-, et al.
(författare)
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Tools and considerations for mitochondrial haplogroup assignment
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Phylogenetic information can be used to infer maternal biogeographic ancestry and provide a valuable quality control (QC) check of mitochondrial DNA (mtDNA) data, identifying errors in the data such as artificial recombination and phantom mutations. Additionally, the phylogeny guides mtDNA nomenclature, which is crucial for forensic searches. This study compared three haplogrouping tools and their ability to provide proper guidance based on the predicted phylogeny. The Mitochondrial Haplogrouper tool of the AFDIL-QIAGEN mtDNA Expert (AQME), a plug-in for the CLC Genomics Workbench, and the web-based tools HaploGrep2 and EMPOP were included in the evaluation. Haplogroups were determined for 92 diverse mtDNA haplotypes by the three tools based on four regions: the entire mitochondrial genome (mitogenome), control region (CR), hypervariable segment 1 and 2 (HVS1-2) regions, and HVS1 only. There were only two differences (out of 92) between all three tools when using the mitogenome, and in these instances the haplogroups were less precise by one or two nodes. Haplogroup assignments for the CR and HVS1-2 were similar; though less precise haplogroups resulted for these HVS1-2 haplotypes compared to the CR due to haplogroup-diagnostic mutations outside the queried region. As an important QC aspect, the comparison between the haplogroup predictions of authentic and artificial haplotypes showed that it is possible to identify recombinant mitogenome haplotypes from two large (~8500-bp) amplicons, but the differentiation is more difficult with HVS1-2 “artificial” haplotypes. Overall, the tools performed similarly, but EMPOP’s SAM2 produced more precise haplogroup predictions than AQME and HaploGrep2 across all haplogroups and regions. An important consideration when using any haplogrouping tool is that the haplogroup identified is only a prediction, particularly when based on smaller regions. All three tools provided valuable phylogenetic information to enable QC of mtDNA data, but critical review of the predicted haplogroup may be required for certain applications.
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| 14. |
- Tehua Lu, Timothy, et al.
(författare)
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An evaluation of the genetic-matched pair study design using genome-wide SNP data from the European population
- 2009
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Ingår i: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 17:7, s. 967-975
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Tidskriftsartikel (refereegranskat)abstract
- Genetic matching potentially provides a means to alleviate the effects of incomplete Mendelian randomization in population-based gene-disease association studies. We therefore evaluated the genetic-matched pair study design on the basis of genome-wide SNP data (309 790 markers; Affymetrix GeneChip Human Mapping 500K Array) from 2457 individuals, sampled at 23 different recruitment sites across Europe. Using pair-wise identity-by-state (IBS) as a matching criterion, we tried to derive a subset of markers that would allow identification of the best overall matching (BOM) partner for a given individual, based on the IBS status for the subset alone. However, our results suggest that, by following this approach, the prediction accuracy is only notably improved by the first 20 markers selected, and increases proportionally to the marker number thereafter. Furthermore, in a considerable proportion of cases (76.0%), the BOM of a given individual, based on the complete marker set, came from a different recruitment site than the individual itself. A second marker set, specifically selected for ancestry sensitivity using singular value decomposition, performed even more poorly and was no more capable of predicting the BOM than randomly chosen subsets. This leads us to conclude that, at least in Europe, the utility of the genetic-matched pair study design depends critically on the availability of comprehensive genotype information for both cases and controls. European Journal of Human Genetics (2009) 17, 967-975; doi:10.1038/ejhg.2008.266; published online 21 January 2009
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| 15. |
- Tillmar, Andreas, et al.
(författare)
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DNA Commission of the International Society for Forensic Genetics ( ISFG): Guidelines on the use of X-STRs in kinship analysis
- 2017
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Ingår i: Forensic Science International. - : ELSEVIER IRELAND LTD. - 1872-4973 .- 1878-0326. ; 29, s. 269-275
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Tidskriftsartikel (refereegranskat)abstract
- Forensic genetic laboratories perform an increasing amount of genetic analyses of the X chromosome, in particular to solve complex cases of kinship analysis. For some biological relationships X-chromosomal markers can be more informative than autosomal markers, and there are a large number of markers, methods and databases that have been described for forensic use. Due to their particular mode of inheritance, and their physical location on a single chromosome, some specific considerations are required when estimating the weight of evidence for X-chromosomal marker DNA data. The DNA Commission of the International Society for Forensic Genetics (ISFG) hereby presents guidelines and recommendations for the use of X-chromosomal markers in kinship analysis with a special focus on the biostatistical evaluation. Linkage and linkage disequilibrium (association of alleles) are of special importance for such evaluations and these concepts and the implications for likelihood calculations are described in more detail. Furthermore it is important to use appropriate computer software that accounts for linkage and linkage disequilibrium among loci, as well as for mutations. Even though some software exist, there is still a need for further improvement of dedicated software. (C) 2017 Elsevier B.V. All rights reserved.
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| 16. |
- Xavier, Catarina, et al.
(författare)
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Evaluation of the VISAGE basic tool for appearance and ancestry inference using ForenSeq® chemistry on the MiSeq FGx® system
- 2022
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Ingår i: Forensic Science International: Genetics. - : Elsevier BV. - 1872-4973. ; 58
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of providing investigative leads when conventional DNA identification methods fail to solve a case can be of extreme relevance to law enforcement. Therefore, the forensic genetics community has focused research towards the broadened use of DNA, particularly for prediction of appearance traits, bio-geographical ancestry and age. The VISible Attributes through GEnomics (VISAGE) Consortium expanded the use of DNA phenotyping by developing new molecular and statistical tools for appearance, age and ancestry prediction. The VISAGE basic tool for appearance (EVC) and ancestry (BGA) prediction was initially developed using Ampliseq chemistry, but here is being evaluated using ForenSeq chemistry. The VISAGE basic tool offers a total of 41 EVC and 115 BGA SNPs and thus provides more predictions, i.e., skin color, than achieved with the ForenSeq DNA Signature Prep kit that is based on 24 EVC and 56 BGA SNPs. Five VISAGE laboratories participated in collaborative experiments to provide foreground for developmental validation of the assay. Assessment of assay performance and quality metrics, reproducibility, sensitivity, inhibitor tolerance and species specificity are described. Furthermore, the assay was tested using challenging samples such as mock casework samples and artificially degraded DNA. Two different analysis strategies were applied for this study and output on genotype calls and read depth was compared. Overall, inter-laboratory, inter-method and concordance with publicly available data were analysed and compared. Finally, the results showed a reliable and robust tool, which can be easily applied for laboratories already using a MiSeq FGx with ForenSeq reagents.
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