scholarly journals The Plateau Method for Forensic DNA SNP Mixture Deconvolution

2017 ◽  
Author(s):  
Darrell O. Ricke ◽  
Joe Isaacson ◽  
James Watkins ◽  
Philip Fremont-Smith ◽  
Tara Boettcher ◽  
...  
Keyword(s):  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
High Throughput Sequencing ◽  
Nucleotide Polymorphisms ◽  
Forensic Dna ◽  
Dna Mixtures ◽  
Single Nucleotide ◽  
Mixture Deconvolution ◽  
Dna Mixture ◽  
Short Tandem

AbstractIdentification of individuals in complex DNA mixtures remains a challenge for forensic analysts. Recent advances in high throughput sequencing (HTS) are enabling analysis of DNA mixtures with expanded panels of Short Tandem Repeats (STRs) and/or Single Nucleotide Polymorphisms (SNPs). We present the plateau method for direct SNP DNA mixture deconvolution into sub-profiles based on differences in contributors’ DNA concentrations in the mixtures in the absence of matching reference profiles. The Plateau method can detect profiles of individuals whose contribution is as low as 1/200 in a DNA mixture (patent pending)1.

scholarly journals TranslucentID: Detecting Individuals with High Confidence in Saturated DNA SNP Mixtures

2018 ◽  
Author(s):  
Darrell O. Ricke ◽  
James Watkins ◽  
Philip Fremont-Smith ◽  
Tara Boettcher ◽  
Eric Schwoebel
Keyword(s):  
High Throughput Sequencing ◽  
Nucleotide Polymorphisms ◽  
Forensic Dna ◽  
Mixture Analysis ◽  
High Confidence ◽  
Dna Mixtures ◽  
Single Nucleotide ◽  
Minor Alleles ◽  
Dna Mixture ◽  
Mixture Samples

AbstractHigh throughput sequencing (HTS) of complex DNA mixtures with single nucleotide polymorphisms (SNPs) panels can identify multiple individuals in forensic DNA mixture samples. SNP mixture analysis relies upon the exclusion of non-contributing individuals with the subset of SNP loci with no detected minor alleles in the mixture. Few, if any, individuals are anticipated to be detectable in saturated mixtures by this mixture analysis approach because of the increased probability of matching random individuals. Being able to identify a subset of the contributors in saturated HTS SNP mixtures is valuable for forensic investigations. A desaturated mixture can be created by treating a set of SNPs with the lowest minor allele ratios as having no minor alleles. Leveraging differences in DNA contributor concentrations in saturated mixtures, we introduce TranslucentID for the identification of a subset of individuals with high confidence who contributed DNA to saturated mixtures by desaturating the mixtures.

scholarly journals Comprehensive Insights Into Forensic Features and Genetic Background of Chinese Northwest Hui Group Using Six Distinct Categories of 231 Molecular Markers

2021 ◽  
Vol 12 ◽  
Author(s):  
Chong Chen ◽  
Xiaoye Jin ◽  
Xingru Zhang ◽  
Wenqing Zhang ◽  
Yuxin Guo ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Single Nucleotide Polymorphisms ◽  
Genetic Background ◽  
Short Tandem Repeats ◽  
Tandem Repeats ◽  
Genetic Relationships ◽  
Population Data ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Short Tandem

The Hui minority is predominantly composed of Chinese-speaking Islamic adherents distributed throughout China, of which the individuals are mainly concentrated in Northwest China. In the present study, we employed the length and sequence polymorphisms-based typing system of 231 molecular markers, i.e., amelogenin, 22 phenotypic-informative single nucleotide polymorphisms (PISNPs), 94 identity-informative single nucleotide polymorphisms (IISNPs), 24 Y-chromosomal short tandem repeats (Y-STRs), 56 ancestry-informative single nucleotide polymorphisms (AISNPs), 7 X-chromosomal short tandem repeats (X-STRs), and 27 autosomal short tandem repeats (A-STRs), into 90 unrelated male individuals from the Chinese Northwest Hui group to comprehensively explore its forensic characteristics and genetic background. Total of 451 length-based and 652 sequence-based distinct alleles were identified from 58 short tandem repeats (STRs) in 90 unrelated Northwest Hui individuals, denoting that the sequence-based genetic markers could pronouncedly provide more genetic information than length-based markers. The forensic characteristics and efficiencies of STRs and IISNPs were estimated, both of which externalized high polymorphisms in the Northwest Hui group and could be further utilized in forensic investigations. No significant departure from the Hardy–Weinberg equilibrium (HWE) expectation was observed after the Bonferroni correction. Additionally, four group sets of reference population data were exploited to dissect the genetic background of the Northwest Hui group separately from different perspectives, which contained 26 populations for 93 IISNPs, 58 populations for 17 Y-STRs, 26 populations for 55 AISNPs (raw data), and 109 populations for 55 AISNPs (allele frequencies). As a result, the analyses based on the Y-STRs indicated that the Northwest Hui group primarily exhibited intimate genetic relationships with reference Hui groups from Chinese different regions except for the Sichuan Hui group and secondarily displayed close genetic relationships with populations from Central and West Asia, as well as several Chinese groups. However, the AISNP analyses demonstrated that the Northwest Hui group shared more intimate relationships with current East Asian populations apart from reference Hui group, harboring the large proportion of ancestral component contributed by East Asia.

scholarly journals Estimating Individual Contributions to Complex DNA SNP Mixtures

2018 ◽  
Author(s):  
Darrell O. Ricke ◽  
Philip Fremont-Smith ◽  
James Watkins ◽  
Tara Boettcher ◽  
Eric Schwoebel
Keyword(s):  
Tandem Repeats ◽  
High Throughput Sequencing ◽  
Massively Parallel Sequencing ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Individual Contributions ◽  
Peak Areas ◽  
Snp Panels ◽  
Forensic Sample ◽  
Short Tandem

ABSTRACTMixture analysis and deconvolution methods can identify both known and unknown individuals contributing to DNA mixtures. These methods may not identify all DNA contributors with the remaining fraction of the mixture being contributed by one or more unknown individuals. The proportion of DNA contributed by individuals to a forensic sample can be estimated using their quantified mixture alleles. For short tandem repeats (STRs), methods to estimate individual contribution concentrations compare capillary electrophoresis peak heights and or peak areas within a mixture. For single nucleotide polymorphisms (SNPs), the major:minor allele ratios or counts, unique to each contributor, can be compared to estimate contributor proportion within the mixture. This article introduces three approaches (mean, median, and slope methods) for estimating individual DNA contributions to forensic mixtures for high throughput sequencing (HTS)/massively parallel sequencing (MPS) SNP panels.

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