scholarly journals The Genetic Chain Rule for Probabilistic Kinship Estimation

2017 ◽  
Author(s):  
Brian S. Helfer ◽  
Philip Fremont-Smith ◽  
Darrell O. Ricke

ABSTRACTAccurate kinship predictions using DNA forensic samples has utility for investigative leads, remains identification, identifying relationships between individuals of interest, etc. High throughput sequencing (HTS) of STRs and single nucleotide polymorphisms (SNPs) is enabling the characterization of larger numbers of loci. Large panels of SNP loci have been proposed for improved mixture analysis of forensic samples. While multiple kinship prediction approaches have been established, we present an approach focusing on these large HTS SNP panels for predicting degree of kinship predictions. Formulas for first degree relatives can be multiplied (chained) together to model extended kinship relationships. Predictions are made using these formulations by calculating log likelihood ratios and selecting the maximum likelihood across the possible relationships. With a panel of 30,000 SNPs evaluated on an in silico dataset, this method can resolve parents from siblings and distinguish 1st, 2nd, and 3rd degree relatives from each other and unrelated individuals.

Author(s):  
Soyeon Bae ◽  
Sohyoung Won ◽  
Heebal Kim

AbstractDue to the advantages of single-nucleotide polymorphisms (SNPs) in forensic science, many forensic SNP panels have been developed. However, the existing SNP panels have a problem that they do not reflect allele frequencies in Koreans or the number of markers is not sufficient to perform paternity testing. Here, we filtered candidate SNPs from the Ansan-Ansung cohort data and selected 200 SNPs with high allele frequencies. To reduce the risk of false inclusion and false exclusion, we calculated likelihood ratios of alleged father-child pairs from simulated families when the alleged father is the true father, the close relative of the true father, and the random man. As a result, we estimated that 160 SNPs were needed to perform paternity testing. Furthermore, we performed validation using Twin-Family cohort data. When 160 selected SNPs were used to calculate the likelihood ratio, paternity and non-paternity were accurately distinguished. Our set of 160 SNPs could be useful for paternity testing in Koreans.


2018 ◽  
Author(s):  
Darrell O. Ricke ◽  
Philip Fremont-Smith ◽  
James Watkins ◽  
Tara Boettcher ◽  
Eric Schwoebel

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.


2015 ◽  
Author(s):  
Sanaa Afroz Ahmed ◽  
Chien-Chi Lo ◽  
Po-E Li ◽  
Karen W Davenport ◽  
Patrick S.G. Chain

Next-generation sequencing is increasingly being used to examine closely related organisms. However, while genome-wide single nucleotide polymorphisms (SNPs) provide an excellent resource for phylogenetic reconstruction, to date evolutionary analyses have been performed using different ad hoc methods that are not often widely applicable across different projects. To facilitate the construction of robust phylogenies, we have developed a method for genome-wide identification/characterization of SNPs from sequencing reads and genome assemblies. Our phylogenetic and molecular evolutionary (PhaME) analysis software is unique in its ability to take reads and draft/complete genome(s) as input, derive core genome alignments, identify SNPs, construct phylogenies and perform evolutionary analyses. Several examples using genomes and read datasets for bacterial, eukaryotic and viral linages demonstrate the broad and robust functionality of PhaME. Furthermore, the ability to incorporate raw metagenomic reads from clinical samples with suspected infectious agents shows promise for the rapid phylogenetic characterization of pathogens within complex samples.


2021 ◽  
Author(s):  
ZHIYONG Chen ◽  
Yancen He ◽  
Yasir Iqbal ◽  
Yanlan Shi ◽  
Hongmei Huang ◽  
...  

Abstract Background: Miscanthus, which is a leading dedicated-energy grass in Europe and in parts of Asia, is expected to play a key role in the development of the future bioeconomy. However, due to its complex genetic background, it is difficult to investigate phylogenetic relationships and the evolution of gene function in this genus. Here, we investigated 50 Miscanthus germplasms: 1 female parent (M. lutarioriparius), 30 candidate male parents (M. lutarioriparius, M. sinensis, and M. sacchariflorus), and 19 offspring. We used high-throughput Specific-Locus Amplified Fragment sequencing (SLAF-seq) to identify informative single nucleotide polymorphisms (SNPs) in all germplasms.Results: We identified 800,081 SLAF tags, of which 160,368 were polymorphic. Each tag was 264–364 bp long. The obtained SNPs were used to investigate genetic relationships within Miscanthus. We constructed a phylogenetic tree of the 50 germplasms using the obtained SNPs, and found that the germplasms fell into two clades: one clade of M. sinensis only and one clade that included the offspring, M. lutarioriparius, and M. sacchariflorus. Genetic cluster analysis indicated that M. lutarioriparius germplasm C3 was the most likely male parent of the offspring.Conclusions: As a high-throughput sequencing method, SLAF-seq can be used to identify informative SNPs in Miscanthus germplasms and to rapidly characterize genetic relationships within this genus. Our results will support the development of breeding programs utilizing Miscanthus cultivars with elite biomass- or fiber-production potential.


Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2073
Author(s):  
Nicolás Galarce ◽  
Beatriz Escobar ◽  
Eduard Martínez ◽  
Natalia Alvarado ◽  
Gabriela Peralta ◽  
...  

Canine brucellosis caused by Brucella canis is a zoonotic disease that causes reproductive alterations in dogs, such as infertility, abortion, and epididymitis. This pathogen is especially prevalent in South America, and due to the lack of official control programs and the growing trend of adopting dogs it constitutes a public health risk that must be addressed. The aim of this study was to determine the prevalence of B. canis infection in kennel, shelter, and household dogs and to characterize the genomic properties of circulating strains, including ure and virB operons and omp25/31 genes. Samples from 771 dogs were obtained, and the infection was detected by blood culture and/or serology in 7.0% of the animals. The complete ure and virB operons and the omp25/31 genes were detected. Interestingly, we found different single-nucleotide polymorphisms (SNPs) in some of the analyzed genes, which could mean a change in the fitness or virulence of these strains. This study provides further evidence about dogs as a source of B. canis strains that can infect people. This also highlights the need to implement official control programs, including the mandatory testing of dogs, especially stray dogs, before adoption.


2011 ◽  
Vol 4 (6) ◽  
pp. 336-344 ◽  
Author(s):  
Miriam Enriqueta Nieves-Ramirez ◽  
Oswaldo Partida-Rodriguez ◽  
Pedro Eduardo Alegre-Crespo ◽  
Maria del Carmen Tapia-Lugo ◽  
Martha Esthela Perez-Rodriguez

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Weizhuo Zhu ◽  
Yiyi Guo ◽  
Yeke Chen ◽  
Dezhi Wu ◽  
Lixi Jiang

Abstract Background Transcription factors GATAs are involved in plant developmental processes and respond to environmental stresses through binding DNA regulatory regions to regulate their downstream genes. However, little information on the GATA genes in Brassica napus is available. The release of the reference genome of B. napus provides a good opportunity to perform a genome-wide characterization of GATA family genes in rapeseed. Results In this study, 96 GATA genes randomly distributing on 19 chromosomes were identified in B. napus, which were classified into four subfamilies based on phylogenetic analysis and their domain structures. The amino acids of BnGATAs were obvious divergence among four subfamilies in terms of their GATA domains, structures and motif compositions. Gene duplication and synteny between the genomes of B. napus and A. thaliana were also analyzed to provide insights into evolutionary characteristics. Moreover, BnGATAs showed different expression patterns in various tissues and under diverse abiotic stresses. Single nucleotide polymorphisms (SNPs) distributions of BnGATAs in a core collection germplasm are probably associated with functional disparity under environmental stress condition in different genotypes of B. napus. Conclusion The present study was investigated genomic structures, evolution features, expression patterns and SNP distributions of 96 BnGATAs. The results enrich our understanding of the GATA genes in rapeseed.


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