scholarly journals Genome Diversity in Maize

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Victor Llaca ◽  
Matthew A. Campbell ◽  
Stéphane Deschamps
Keyword(s):  
Structural Variation ◽  
Genome Structure ◽  
Primate Species ◽  
Maize Genome ◽  
Genome Diversity ◽  
Model Species ◽  
The Past ◽  
Genome Complexity ◽  
Genome Wide ◽  
Sequencing Platforms

Zea mays (maize) has historically been used as a model species for genetics, development, physiology and more recently, genome structure. The maize genome is complex with striking intraspecific variation in gene order, repetitive DNA content, and allelic content exceeding the levels observed between primate species. Maize genome complexity is primarily driven by polyploidization and explosive amplification of LTR retrotransposons, with the counteracting effect of unequal and illegitimate crossover. Transposable elements have been shown to capture genic content, create chimeras, and amplify those sequences via transposition. New sequencing platforms and hybridization-based strategies have appeared over the past decade which are being applied to maize and providing the first genome-wide comprehensive view of structural variation and will provide the basis for investigating the interplay between repeats and genes as well as the amount of species level diversity within maize.

scholarly journals Genome-wide Imputation Using the Practical Haplotype Graph in the Heterozygous Crop Cassava

2021 ◽  
Author(s):  
Evan M Long ◽  
Peter J. Bradbury ◽  
Cinta Romay ◽  
Edward Buckler ◽  
Kelly R Robbins
Keyword(s):  
Cross Validation ◽  
Imputation Accuracy ◽  
Genotype Imputation ◽  
Model Species ◽  
The Past ◽  
Genome Wide ◽  
Limited Input Data ◽  
The Cost ◽  
Genome Information ◽  
Validation Testing

Genomic applications such as genomic selection and genome-wide association have become increasingly common since the advent of genome sequencing. The cost of sequencing has decreased in the past two decades, however genotyping costs are still prohibitive to gathering large datasets for these genomic applications, especially in non-model species where resources are less abundant. Genotype imputation makes it possible to infer whole genome information from limited input data, making large sampling for genomic applications more feasible. Imputation becomes increasingly difficult in heterozygous species where haplotypes must be phased. The Practical Haplotype Graph is a recently developed tool that can accurately impute genotypes, using a reference panel of haplotypes. We showcase the ability of the Practical Haplotype Graph to impute genomic information in the highly heterozygous crop cassava (Manihot esculenta). Accurately phased haplotypes were sampled from runs of homozygosity across a diverse panel of individuals to populate PHG, which proved more accurate than relying on computational phasing methods. The Practical Haplotype Graph achieved high imputation accuracy, using sparse skim-sequencing input, which translated to substantial genomic prediction accuracy in cross validation testing. The Practical Haplotype Graph showed improved imputation accuracy, compared to a standard imputation tool Beagle, especially in predicting rare alleles.

scholarly journals Genome-wide Imputation Using the Practical Haplotype Graph in the Heterozygous Crop Cassava

2021 ◽  
Author(s):  
Evan M Long ◽  
Peter J Bradbury ◽  
M Cinta Romay ◽  
Edward S Buckler ◽  
Kelly R Robbins
Keyword(s):  
Cross Validation ◽  
Imputation Accuracy ◽  
Genotype Imputation ◽  
Model Species ◽  
The Past ◽  
Genome Wide ◽  
Limited Input Data ◽  
The Cost ◽  
Genome Information ◽  
Validation Testing

Abstract Genomic applications such as genomic selection and genome-wide association have become increasingly common since the advent of genome sequencing. The cost of sequencing has decreased in the past two decades, however genotyping costs are still prohibitive to gathering large datasets for these genomic applications, especially in non-model species where resources are less abundant. Genotype imputation makes it possible to infer whole genome information from limited input data, making large sampling for genomic applications more feasible. Imputation becomes increasingly difficult in heterozygous species where haplotypes must be phased. The Practical Haplotype Graph is a recently developed tool that can accurately impute genotypes, using a reference panel of haplotypes. We showcase the ability of the Practical Haplotype Graph to impute genomic information in the highly heterozygous crop cassava (Manihot esculenta). Accurately phased haplotypes were sampled from runs of homozygosity across a diverse panel of individuals to populate PHG, which proved more accurate than relying on computational phasing methods. The Practical Haplotype Graph achieved high imputation accuracy, using sparse skim-sequencing input, which translated to substantial genomic prediction accuracy in cross validation testing. The Practical Haplotype Graph showed improved imputation accuracy, compared to a standard imputation tool Beagle, especially in predicting rare alleles.

scholarly journals Subtype-associated epigenomic landscape and 3D genome structure in bladder cancer

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Tejaswi Iyyanki ◽  
Baozhen Zhang ◽  
Qixuan Wang ◽  
Ye Hou ◽  
Qiushi Jin ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Transcription Factor ◽  
Cancer Cell ◽  
Genome Structure ◽  
Transcription Factor Binding ◽  
Specific Gene ◽  
Open Chromatin ◽  
Factor Binding ◽  
3D Genome ◽  
Genome Wide

Abstract Muscle-invasive bladder cancers are characterized by their distinct expression of luminal and basal genes, which could be used to predict key clinical features such as disease progression and overall survival. Transcriptionally, FOXA1, GATA3, and PPARG are shown to be essential for luminal subtype-specific gene regulation and subtype switching, while TP63, STAT3, and TFAP2 family members are critical for regulation of basal subtype-specific genes. Despite these advances, the underlying epigenetic mechanisms and 3D chromatin architecture responsible for subtype-specific regulation in bladder cancer remain unknown. Result We determine the genome-wide transcriptome, enhancer landscape, and transcription factor binding profiles of FOXA1 and GATA3 in luminal and basal subtypes of bladder cancer. Furthermore, we report the first-ever mapping of genome-wide chromatin interactions by Hi-C in both bladder cancer cell lines and primary patient tumors. We show that subtype-specific transcription is accompanied by specific open chromatin and epigenomic marks, at least partially driven by distinct transcription factor binding at distal enhancers of luminal and basal bladder cancers. Finally, we identify a novel clinically relevant transcription factor, Neuronal PAS Domain Protein 2 (NPAS2), in luminal bladder cancers that regulates other subtype-specific genes and influences cancer cell proliferation and migration. Conclusion In summary, our work identifies unique epigenomic signatures and 3D genome structures in luminal and basal urinary bladder cancers and suggests a novel link between the circadian transcription factor NPAS2 and a clinical bladder cancer subtype.

scholarly journals Aging-associated distinctive DNA methylation changes of LINE-1 retrotransposons in pure cell-free DNA from human blood

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wardah Mahmood ◽  
Lars Erichsen ◽  
Pauline Ott ◽  
Wolfgang A. Schulz ◽  
Johannes C. Fischer ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cell Free Dna ◽  
The Past ◽  
Free Dna ◽  
Genome Wide ◽  
Cancerous Cell ◽  
Pure Cell ◽  
Epigenetic Biomarker ◽  
Methylation Patterns ◽  
Cancerous Cells

AbstractLINE-1 hypomethylation of cell-free DNA has been described as an epigenetic biomarker of human aging. However, in the past, insufficient differentiation between cellular and cell-free DNA may have confounded analyses of genome-wide methylation levels in aging cells. Here we present a new methodological strategy to properly and unambiguously extract DNA methylation patterns of repetitive, as well as single genetic loci from pure cell-free DNA from peripheral blood. Since this nucleic acid fraction originates mainly in apoptotic, senescent and cancerous cells, this approach allows efficient analysis of aged and cancerous cell-specific DNA methylation patterns for diagnostic and prognostic purposes. Using this methodology, we observe a significant age-associated erosion of LINE-1 methylation in cfDNA suggesting that the threshold of hypomethylation sufficient for relevant LINE-1 activation and consequential harmful retrotransposition might be reached at higher age. We speculate that this process might contribute to making aging the main risk factor for many cancers.

scholarly journals Czechoslovakian Wolfdog Genomic Divergence from Its Ancestors Canis lupus, German Shepherd Dog, and Different Sheepdogs of European Origin

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 832
Author(s):  
Nina Moravčíková ◽  
Radovan Kasarda ◽  
Radoslav Židek ◽  
Luboš Vostrý ◽  
Hana Vostrá-Vydrová ◽  
...  
Keyword(s):  
Demographic History ◽  
Genome Structure ◽  
Principal Component ◽  
Genetic Distances ◽  
Nucleotide Polymorphisms ◽  
German Shepherd ◽  
German Shepherd Dog ◽  
Genome Wide ◽  
Scale Population ◽  
History Effect

This study focused on the genomic differences between the Czechoslovakian wolfdog (CWD) and its ancestors, the Grey wolf (GW) and German Shepherd dog. The Saarloos wolfdog and Belgian Shepherd dog were also included to study the level of GW genetics retained in the genome of domesticated breeds. The dataset consisted of 131 animals and 143,593 single nucleotide polymorphisms (SNPs). The effects of demographic history on the overall genome structure were determined by screening the distribution of the homozygous segments. The genetic variance distributed within and between groups was quantified by genetic distances, the FST index, and discriminant analysis of principal components. Fine-scale population stratification due to specific morphological and behavioural traits was assessed by principal component and factorial analyses. In the CWD, a demographic history effect was manifested mainly in a high genome-wide proportion of short homozygous segments corresponding to a historical load of inbreeding derived from founders. The observed proportion of long homozygous segments indicated that the inbreeding events shaped the CWD genome relatively recently compared to other groups. Even if there was a significant increase in genetic similarity among wolf-like breeds, they were genetically separated from each other. Moreover, this study showed that the CWD genome carries private alleles that are not found in either wolves or other dog breeds analysed in this study.

Genome-wide mining of perfect microsatellites and tetranucleotide orthologous microsatellites estimates in six primate species

Gene ◽  
2018 ◽  
Vol 643 ◽  
pp. 124-132 ◽  
Author(s):  
Yongtao Xu ◽  
Wujiao Li ◽  
Zongxiu Hu ◽  
Tao Zeng ◽  
Yongmei Shen ◽  
...  
Keyword(s):  
Primate Species ◽  
Genome Wide

scholarly journals Genetic epidemiology and Mendelian randomization for informing disease therapeutics: conceptual and methodological challenges

2017 ◽  
Author(s):  
Lavinia Paternoster ◽  
Kate Tilling ◽  
George Davey Smith
Keyword(s):  
Genetic Epidemiology ◽  
Mendelian Randomization ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Disease Treatment ◽  
The Past ◽  
Genome Wide ◽  
Perceived Benefit ◽  
Progression Of Disease ◽  
High Yields

The past decade has been proclaimed as a hugely successful era of gene discovery through the high yields of many genome-wide association studies (GWAS). However, much of the perceived benefit of such discoveries lies in the promise that the identification of genes that influence disease would directly translate into the identification of potential therapeutic targets (1-4), but this has yet to be realised at a level reflecting expectation. One reason for this, we suggest, is that GWAS to date have generally not focused on phenotypes that directly relate to the progression of disease, and thus speak to disease treatment.

scholarly journals Genome-Wide Identification of 5-Methylcytosine Sites in Bacterial Genomes By High-Throughput Sequencing of MspJI Restriction Fragments

2021 ◽  
Author(s):  
Brian P. Anton ◽  
Alexey Fomenkov ◽  
Victoria Wu ◽  
Richard J. Roberts
Keyword(s):  
Single Molecule ◽  
Dna Sequences ◽  
High Throughput Sequencing ◽  
Cost Effective ◽  
Restriction Enzymes ◽  
Specific Sequence ◽  
Genome Wide ◽  
Cost Effective Alternative ◽  
Simple Column ◽  
Sequencing Platforms

ABSTRACTSingle-molecule Real-Time (SMRT) sequencing can easily identify sites of N6-methyladenine and N4-methylcytosine within DNA sequences, but similar identification of 5-methylcytosine sites is not as straightforward. In prokaryotic DNA, methylation typically occurs within specific sequence contexts, or motifs, that are a property of the methyltransferases that “write” these epigenetic marks. We present here a straightforward, cost-effective alternative to both SMRT and bisulfite sequencing for the determination of prokaryotic 5-methylcytosine methylation motifs. The method, called MFRE-Seq, relies on excision and isolation of fully methylated fragments of predictable size using MspJI-Family Restriction Enzymes (MFREs), which depend on the presence of 5-methylcytosine for cleavage. We demonstrate that MFRE-Seq is compatible with both Illumina and Ion Torrent sequencing platforms and requires only a digestion step and simple column purification of size-selected digest fragments prior to standard library preparation procedures. We applied MFRE-Seq to numerous bacterial and archaeal genomic DNA preparations and successfully confirmed known motifs and identified novel ones. This method should be a useful complement to existing methodologies for studying prokaryotic methylomes and characterizing the contributing methyltransferases.

scholarly journals The Toolbox for Untangling Chromosome Architecture in Immune Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Shuai Liu ◽  
Keji Zhao
Keyword(s):  
Gene Expression ◽  
Immune Cells ◽  
Spatial Organization ◽  
Chromosome Structure ◽  
Immune Cell ◽  
Genome Structure ◽  
Chromosome Architecture ◽  
The Past ◽  
Important Player ◽  
The Way

The code of life is not only encrypted in the sequence of DNA but also in the way it is organized into chromosomes. Chromosome architecture is gradually being recognized as an important player in regulating cell activities (e.g., controlling spatiotemporal gene expression). In the past decade, the toolbox for elucidating genome structure has been expanding, providing an opportunity to explore this under charted territory. In this review, we will introduce the recent advancements in approaches for mapping spatial organization of the genome, emphasizing applications of these techniques to immune cells, and trying to bridge chromosome structure with immune cell activities.

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