scholarly journals Linear Assembly of a Human Y Centromere

2017 ◽  
Author(s):  
Miten Jain ◽  
Hugh E. Olsen ◽  
Daniel J. Turner ◽  
David Stoddart ◽  
Kira V. Bulazel ◽  
...  
Keyword(s):  
Tandem Repeats ◽  
Centromeric Region ◽  
Reference Sequence ◽  
Nanopore Sequencing ◽  
Linear Assembly ◽  
Sequencing Strategy ◽  
Human Genome Reference Sequence ◽  
Human Y Chromosome ◽  
Human Genome Reference

The human genome reference sequence remains incomplete due to the challenge of assembling long tracts of near-identical tandem repeats-in centromeric regions. To address this, we have implemented a nanopore sequencing strategy to generate high quality reads that span hundreds of kilobases of highly repetitive DNAs. Here, we use this advance to produce a sequence assembly and characterization of the centromeric region of a human Y chromosome.

A legacy of the “1% program” – The “Chinese Chapter” of the human genome reference sequence

2018 ◽  
Vol 45 (11) ◽  
pp. 565-568
Author(s):  
Wei Dong ◽  
Xiaoling Wang ◽  
Zhi Xia ◽  
Xiuqing Zhang ◽  
Huanming Yang
Keyword(s):  
Human Genome ◽  
Reference Sequence ◽  
Human Genome Reference Sequence ◽  
Human Genome Reference

scholarly journals Introducing ribosomal tandem repeat barcoding for fungi

2018 ◽  
Author(s):  
Christian Wurzbacher ◽  
Ellen Larsson ◽  
Johan Bengtsson-Palme ◽  
Silke Van den Wyngaert ◽  
Sten Svantesson ◽  
...  
Keyword(s):  
Large Scale ◽  
Tandem Repeats ◽  
Reference Data ◽  
Reference Sequence ◽  
Herbarium Specimens ◽  
Nanopore Sequencing ◽  
Desktop Computer ◽  
Third Generation Sequencing ◽  
Ribosomal Operon ◽  
Sequencing Facility

AbstractSequence analysis of the various ribosomal genetic markers is the dominant molecular method for identification and description of fungi. However, there is little agreement on what ribosomal markers should be used, and research groups utilize different markers depending on what fungal groups are targeted. New environmental fungal lineages known only from DNA data reveal significant gaps in the coverage of the fungal kingdom both in terms of taxonomy and marker coverage in the reference sequence databases. In order to integrate references covering all of the ribosomal markers, we present three sets of general primers that allow the amplification of the complete ribosomal operon from the ribosomal tandem repeats. The primers cover all ribosomal markers (ETS, SSU, ITS1, 5.8S, ITS2, LSU, and IGS) from the 5’ end of the ribosomal operon all the way to the 3’ end. We coupled these primers successfully with third generation sequencing (PacBio and Nanopore sequencing) to showcase our approach on authentic fungal herbarium specimens. In particular, we were able to generate high-quality reference data with Nanopore sequencing in a high-throughput manner, showing that the generation of reference data can be achieved on a regular desktop computer without the need for a large-scale sequencing facility. The quality of the Nanopore generated sequences was 99.85 %, which is comparable with the 99.78 % accuracy described for Sanger sequencing. With this work, we hope to stimulate the generation of a new comprehensive standard of ribosomal reference data with the ultimate aim to close the huge gaps in our reference datasets.

scholarly journals Envisioning the next human genome reference

2021 ◽  
Vol 14 (12) ◽  
Author(s):  
Monkol Lek ◽  
Elaine R. Mardis
Keyword(s):  
Precision Medicine ◽  
Human Genome ◽  
Reference Sequence ◽  
Ethnic Representation ◽  
Genomic Studies ◽  
Human Genome Reference Sequence ◽  
Human Genome Reference

Summary: We provide an Editorial perspective on approaches to improve ethnic representation in the human genome reference sequence, enabling its widespread use in genomic studies and precision medicine to benefit all peoples.

scholarly journals Physical mapping of repetitive oligonucleotides facilitates the establishment of a genome map-based karyotype to identify chromosomal variations in peanut

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Liuyang Fu ◽  
Qian Wang ◽  
Lina Li ◽  
Tao Lang ◽  
Junjia Guo ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Physical Mapping ◽  
Tandem Repeats ◽  
Genetic Research ◽  
Diploid Species ◽  
Reference Sequence ◽  
A Genome ◽  
Genome Map ◽  
Chromosomal Variants

Abstract Background Chromosomal variants play important roles in crop breeding and genetic research. The development of single-stranded oligonucleotide (oligo) probes simplifies the process of fluorescence in situ hybridization (FISH) and facilitates chromosomal identification in many species. Genome sequencing provides rich resources for the development of oligo probes. However, little progress has been made in peanut due to the lack of efficient chromosomal markers. Until now, the identification of chromosomal variants in peanut has remained a challenge. Results A total of 114 new oligo probes were developed based on the genome-wide tandem repeats (TRs) identified from the reference sequences of the peanut variety Tifrunner (AABB, 2n = 4x = 40) and the diploid species Arachis ipaensis (BB, 2n = 2x = 20). These oligo probes were classified into 28 types based on their positions and overlapping signals in chromosomes. For each type, a representative oligo was selected and modified with green fluorescein 6-carboxyfluorescein (FAM) or red fluorescein 6-carboxytetramethylrhodamine (TAMRA). Two cocktails, Multiplex #3 and Multiplex #4, were developed by pooling the fluorophore conjugated probes. Multiplex #3 included FAM-modified oligo TIF-439, oligo TIF-185-1, oligo TIF-134-3 and oligo TIF-165. Multiplex #4 included TAMRA-modified oligo Ipa-1162, oligo Ipa-1137, oligo DP-1 and oligo DP-5. Each cocktail enabled the establishment of a genome map-based karyotype after sequential FISH/genomic in situ hybridization (GISH) and in silico mapping. Furthermore, we identified 14 chromosomal variants of the peanut induced by radiation exposure. A total of 28 representative probes were further chromosomally mapped onto the new karyotype. Among the probes, eight were mapped in the secondary constrictions, intercalary and terminal regions; four were B genome-specific; one was chromosome-specific; and the remaining 15 were extensively mapped in the pericentric regions of the chromosomes. Conclusions The development of new oligo probes provides an effective set of tools which can be used to distinguish the various chromosomes of the peanut. Physical mapping by FISH reveals the genomic organization of repetitive oligos in peanut chromosomes. A genome map-based karyotype was established and used for the identification of chromosome variations in peanut following comparisons with their reference sequence positions.

scholarly journals Characterization of the Genomic Xist Locus in Rodents Reveals Conservation of Overall Gene Structure and Tandem Repeats but Rapid Evolution of Unique Sequence

2001 ◽  
Vol 11 (5) ◽  
pp. 833-849 ◽  
Author(s):  
T. B. Nesterova ◽  
S. Ya. Slobodyanyuk ◽  
E. A. Elisaphenko ◽  
A. I. Shevchenko ◽  
C. Johnston ◽  
...  
Keyword(s):  
Gene Structure ◽  
Tandem Repeats ◽  
Rapid Evolution ◽  
Unique Sequence ◽  
Xist Locus

scholarly journals Nanopore-Sequencing Characterization of the Gut Microbiota of Melolontha melolontha Larvae: Contribution to Protection against Entomopathogenic Nematodes?

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 396
Author(s):  
Ewa Sajnaga ◽  
Marcin Skowronek ◽  
Agnieszka Kalwasińska ◽  
Waldemar Kazimierczak ◽  
Karolina Ferenc ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Entomopathogenic Nematodes ◽  
Bacterial Species ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Nanopore Sequencing ◽  
Bacterial Phyla ◽  
Melolontha Melolontha

This study focused on the potential relationships between midgut microbiota of the common cockchafer Melolontha melolontha larvae and their resistance to entomopathogenic nematodes (EPN) infection. We investigated the bacterial community associated with control and unsusceptible EPN-exposed insects through nanopore sequencing of the 16S rRNA gene. Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the most abundant bacterial phyla within the complex and variable midgut microbiota of the wild M. melolontha larvae. The core microbiota was found to include 82 genera, which accounted for 3.4% of the total number of identified genera. The EPN-resistant larvae differed significantly from the control ones in the abundance of many genera belonging to the Actinomycetales, Rhizobiales, and Clostridiales orders. Additionally, the analysis of the microbiome networks revealed different sets of keystone midgut bacterial genera between these two groups of insects, indicating differences in the mutual interactions between bacteria. Finally, we detected Xenorhabdus and Photorhabdus as gut residents and various bacterial species exhibiting antagonistic activity against these entomopathogens. This study paves the way to further research aimed at unravelling the role of the host gut microbiota on the output of EPN infection, which may contribute to enhancement of the efficiency of nematodes used in eco-friendly pest management.

scholarly journals Novel sequencing strategy for repetitive DNA in a Drosophila BAC clone reveals that the centromeric region of the Y chromosome evolved from a telomere†

2009 ◽  
Vol 37 (7) ◽  
pp. 2264-2273 ◽  
Author(s):  
María Méndez-Lago ◽  
Jadwiga Wild ◽  
Siobhan L. Whitehead ◽  
Alan Tracey ◽  
Beatriz de Pablos ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Repetitive Dna ◽  
Centromeric Region ◽  
Bac Clone ◽  
Sequencing Strategy

scholarly journals How Long Are Long Tandem Repeats? A Challenge for Current Methods of Whole-Genome Sequence Assembly: The Case of Satellites in Caenorhabditis elegans

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 500
Author(s):  
Juan A. Subirana ◽  
Xavier Messeguer
Keyword(s):  
Caenorhabditis Elegans ◽  
Sanger Sequencing ◽  
Tandem Repeats ◽  
Whole Genome Sequence ◽  
Nanopore Sequencing ◽  
Original Sequence ◽  
Genome Sequence Assembly ◽  
Long Read ◽  
Genomic Regions ◽  
Caenorhabditis Elegans Genome

Repetitive genome regions have been difficult to sequence, mainly because of the comparatively small size of the fragments used in assembly. Satellites or tandem repeats are very abundant in nematodes and offer an excellent playground to evaluate different assembly methods. Here, we compare the structure of satellites found in three different assemblies of the Caenorhabditis elegans genome: the original sequence obtained by Sanger sequencing, an assembly based on PacBio technology, and an assembly using Nanopore sequencing reads. In general, satellites were found in equivalent genomic regions, but the new long-read methods (PacBio and Nanopore) tended to result in longer assembled satellites. Important differences exist between the assemblies resulting from the two long-read technologies, such as the sizes of long satellites. Our results also suggest that the lengths of some annotated genes with internal repeats which were assembled using Sanger sequencing are likely to be incorrect.

scholarly journals Genomic characterization of 99 viruses from the bunyavirus families Nairoviridae, Peribunyaviridae, and Phenuiviridae, including 35 previously unsequenced viruses

2021 ◽  
Vol 17 (3) ◽  
pp. e1009315
Author(s):  
Marylee L. Kapuscinski ◽  
Nicholas A. Bergren ◽  
Brandy J. Russell ◽  
Justin S. Lee ◽  
Erin M. Borland ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Reference Sequence ◽  
Large Sample Size ◽  
Emerging Pathogens ◽  
Genome Sequences ◽  
Pathogenic Potential ◽  
Genomic Characterization ◽  
Response Decisions ◽  
Rapid Characterization

Bunyaviruses (Negarnaviricota: Bunyavirales) are a large and diverse group of viruses that include important human, veterinary, and plant pathogens. The rapid characterization of known and new emerging pathogens depends on the availability of comprehensive reference sequence databases that can be used to match unknowns, infer evolutionary and pathogenic potential, and make response decisions in an evidence-based manner. In this study, we determined the coding-complete genome sequences of 99 bunyaviruses in the Centers for Disease Control and Prevention’s Arbovirus Reference Collection, focusing on orthonairoviruses (family Nairoviridae), orthobunyaviruses (Peribunyaviridae), and phleboviruses (Phenuiviridae) that either completely or partially lacked genome sequences. These viruses had been collected over 66 years from 27 countries from vertebrates and arthropods representing 37 genera. Many of the viruses had been characterized serologically and through experimental infection of animals but were isolated in the pre-sequencing era. We took advantage of our unusually large sample size to systematically evaluate genomic characteristics of these viruses, including reassortment, and co-infection. We corroborated our findings using several independent molecular and virologic approaches, including Sanger sequencing of 197 genome segments, and plaque isolation of viruses from putative co-infected virus stocks. This study contributes to the described genetic diversity of bunyaviruses and will enhance the capacity to characterize emerging human pathogenic bunyaviruses.

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