Goat is an important source of milk, meat, and fiber, especially in developing countries. An advantage of goats as livestock is the low maintenance requirements and high adaptability compared to other milk producers. The global population of domestic goats exceeds 800 million. In Africa, goat production is characterized by low productivity levels, and attempts to introduce more productive breeds have met with poor success due in part to nutritional constraints. It has been suggested that incorporation of selective breeding within the herds adapted for survival could represent one approach to improving food security across Africa. A recently produced genome assembly…
Significant advances in bioinformatics tool development have been made to more efficiently leverage and deliver high-quality genome assemblies with PacBio long-read data. Current data throughput of SMRT Sequencing delivers average read lengths ranging from 10-15 kb with the longest reads exceeding 40 kb. This has resulted in consistent demonstration of a minimum 10-fold improvement in genome assemblies with contig N50 in the megabase range compared to assemblies generated using only short- read technologies. This poster highlights recent advances and resources available for advanced bioinformaticians and developers interested in the current state-of-the-art large genome solutions available as open-source code from PacBio…
Whole genome sequencing can provide comprehensive information important for determining the biochemical and genetic nature of all elements inside a genome. The high-quality genome references produced from past genome projects and advances in short-read sequencing technologies have enabled quick and cheap analysis for simple variants. However even with the focus on genome-wide resequencing for SNPs, the heritability of more than 50% of human diseases remains elusive. For non-human organisms, high-contiguity references are deficient, limiting the analysis of genomic features. The long and unbiased reads from single molecule, real-time (SMRT) Sequencing and new de novo assembly approaches have demonstrated the ability…
2015 SMRT Informatics Developers Conference Presentation Slides: Sergey Koren of National Biodefense Analysis and Countermeasures Center (NBACC) provided an overview of the MHAP algorithm, a method for assembling large genomes with Sing-Molecule Sequencing and locality sensitive hashing. Using MHAP, Koren produced a human assembly (CHM1) with a contig N50 of >23 Mb.
The Genome in a Bottle Consortium is developing the reference materials, reference methods , and reference data n
Purpose: Clinical laboratories, research laboratories and technology developers all need DNA samples with reliably known genotypes in order to help validate and improve their methods. The Genome in a Bottle Consortium (genomeinabottle.org) has been developing Reference Materials with high-accuracy whole genome sequences to support these efforts.Methodology: Our pilot reference material is based on Coriell sample NA12878 and was released in May 2015 as NIST RM 8398 (tinyurl.com/giabpilot). To minimize bias and improve accuracy, 11 whole-genome and 3 exome data sets produced using 5 different technologies were integrated using a systematic arbitration method [1]. The Genome in a Bottle Analysis Group…
Single Molecule Real-Time (SMRT) Sequencing was used to generate long reads for whole genome shotgun sequencing of the genome of the`alala (Hawaiian crow). The ‘alala is endemic to Hawaii, and the only surviving lineage of the crow family, Corvidae, in the Hawaiian Islands. The population declined to less than 20 individuals in the 1990s, and today this charismatic species is extinct in the wild. Currently existing in only two captive breeding facilities, reintroduction of the ‘alala is scheduled to begin in the Fall of 2016. Reintroduction efforts will be assisted by information from the ‘alala genome generated and assembled by…
Single-molecule sequencing is now routinely used to assemble complete, high-quality microbial genomes, but these assembly methods have not scaled well to large genomes. To address this problem, we previously introduced the MinHash Alignment Process (MHAP) for overlapping single-molecule reads using probabilistic, locality-sensitive hashing. Integrating MHAP with Celera Assembler (CA) has enabled reference-grade assemblies of model organisms, revealing novel heterochromatic sequences and filling low-complexity gap sequences in the GRCh38 human reference genome. We have applied our methods to assemble the San Clemente goat genome. Combining single-molecule sequencing from Pacific Biosciences and BioNano Genomics generates and assembly that is over 150-fold more…
Reference quality de novo genome assemblies were once solely the domain of large, well-funded genome projects. While next-generation short read technology removed some of the cost barriers, accurate chromosome-scale assembly remains a real challenge. Here we present efforts to de novo assemble the goat (Capra hircus) genome. Through the combination of single-molecule technologies from Pacific Biosciences (sequencing) and BioNano Genomics (optical mapping) coupled with high-throughput chromosome conformation capture sequencing (Hi-C), an inbred San Clemente goat genome has been sequenced and assembled to a high degree of completeness at a relatively modest cost. Starting with 38 million PacBio reads, we integrated…
New technologies and analysis methods are enabling genomic structural variants (SVs) to be detected with ever-increasing accuracy, resolution, and comprehensiveness. Translating these methods to routine research and clinical practice requires robust benchmark sets. We developed the first benchmark set for identification of both false negative and false positive germline SVs, which complements recent efforts emphasizing increasingly comprehensive characterization of SVs. To create this benchmark for a broadly consented son in a Personal Genome Project trio with broadly available cells and DNA, the Genome in a Bottle (GIAB) Consortium integrated 19 sequence-resolved variant calling methods, both alignment- and de novo assembly-based,…
Motivation: Third-generation sequencing technologies can sequence long reads, which is advancing the frontiers of genomics research. However, their high error rates prohibit accurate and efficient downstream analysis. This difficulty has motivated the development of many long read error correction tools, which tackle this problem through sampling redundancy and/or leveraging accurate short reads of the same biological samples. Existing studies to asses these tools use simulated data sets, and are not sufficiently comprehensive in the range of software covered or diversity of evaluation measures used. Results: In this paper, we present a categorization and review of long read error correction methods,…
Completing a genome is an important goal of genome assembly. However, many assemblies, including reference assemblies, are unfinished and have a number of gaps. Long reads obtained from third-generation sequencing (TGS) platforms can help close these gaps and improve assembly contiguity. However, current gap-closure approaches using long reads require extensive runtime and high memory usage. Thus, a fast and memory-efficient approach using long reads is needed to obtain complete genomes.We developed LR_Gapcloser to rapidly and efficiently close the gaps in genome assembly. This tool utilizes long reads generated from TGS sequencing platforms. Tested on de novo assembled gaps, repeat-derived gaps,…
Long reads obtained from third-generation sequencing platforms can help overcome the long-standing challenge of the de novo assembly of sequences for the genomic analysis of non-model eukaryotic organisms. Numerous long-read-aided de novo assemblies have been published recently, which exhibited superior quality of the assembled genomes in comparison with those achieved using earlier second-generation sequencing technologies. Evaluating assemblies is important in guiding the appropriate choice for specific research needs. In this study, we evaluated 10 long-read assemblers using a variety of metrics on Pacific Biosciences (PacBio) data sets from different taxonomic categories with considerable differences in genome size. The results allowed…
The commercial release of third-generation sequencing technologies (TGSTs), giving long and ultra-long sequencing reads, has stimulated the development of new tools for assembling highly contiguous genome sequences with unprecedented accuracy across complex repeat regions. We survey here a wide range of emerging sequencing platforms and analytical tools for de novo assembly, provide background information for each of their steps, and discuss the spectrum of available options. Our decision tree recommends workflows for the generation of a high-quality genome assembly when used in combination with the specific needs and resources of a project.Copyright © 2019 Elsevier Ltd. All rights reserved.