Browsing by Author "Schatz, Michael C"

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    Assemblathon 2: evaluating de novo methods of genome assembly in three vertebrate species.
    (Gigascience, 2013-07-22) Bradnam, Keith R; Fass, Joseph N; Alexandrov, Anton; Baranay, Paul; Bechner, Michael; Birol, Inanç; Boisvert, Sébastien; Chapman, Jarrod A; Chapuis, Guillaume; Chikhi, Rayan; Chitsaz, Hamidreza; Chou, Wen-Chi; Corbeil, Jacques; Del Fabbro, Cristian; Docking, T Roderick; Durbin, Richard; Earl, Dent; Emrich, Scott; Fedotov, Pavel; Fonseca, Nuno A; Ganapathy, Ganeshkumar; Gibbs, Richard A; Gnerre, Sante; Godzaridis, Elénie; Goldstein, Steve; Haimel, Matthias; Hall, Giles; Haussler, David; Hiatt, Joseph B; Ho, Isaac Y; Howard, Jason; Hunt, Martin; Jackman, Shaun D; Jaffe, David B; Jarvis, Erich D; Jiang, Huaiyang; Kazakov, Sergey; Kersey, Paul J; Kitzman, Jacob O; Knight, James R; Koren, Sergey; Lam, Tak-Wah; Lavenier, Dominique; Laviolette, François; Li, Yingrui; Li, Zhenyu; Liu, Binghang; Liu, Yue; Luo, Ruibang; Maccallum, Iain; Macmanes, Matthew D; Maillet, Nicolas; Melnikov, Sergey; Naquin, Delphine; Ning, Zemin; Otto, Thomas D; Paten, Benedict; Paulo, Octávio S; Phillippy, Adam M; Pina-Martins, Francisco; Place, Michael; Przybylski, Dariusz; Qin, Xiang; Qu, Carson; Ribeiro, Filipe J; Richards, Stephen; Rokhsar, Daniel S; Ruby, J Graham; Scalabrin, Simone; Schatz, Michael C; Schwartz, David C; Sergushichev, Alexey; Sharpe, Ted; Shaw, Timothy I; Shendure, Jay; Shi, Yujian; Simpson, Jared T; Song, Henry; Tsarev, Fedor; Vezzi, Francesco; Vicedomini, Riccardo; Vieira, Bruno M; Wang, Jun; Wang, Jun; Worley, Kim C; Yin, Shuangye; Yiu, Siu-Ming; Yuan, Jianying; Zhang, Guojie; Zhang, Hao; Zhou, Shiguo; Korf, Ian F
    BACKGROUND: The process of generating raw genome sequence data continues to become cheaper, faster, and more accurate. However, assembly of such data into high-quality, finished genome sequences remains challenging. Many genome assembly tools are available, but they differ greatly in terms of their performance (speed, scalability, hardware requirements, acceptance of newer read technologies) and in their final output (composition of assembled sequence). More importantly, it remains largely unclear how to best assess the quality of assembled genome sequences. The Assemblathon competitions are intended to assess current state-of-the-art methods in genome assembly. RESULTS: In Assemblathon 2, we provided a variety of sequence data to be assembled for three vertebrate species (a bird, a fish, and snake). This resulted in a total of 43 submitted assemblies from 21 participating teams. We evaluated these assemblies using a combination of optical map data, Fosmid sequences, and several statistical methods. From over 100 different metrics, we chose ten key measures by which to assess the overall quality of the assemblies. CONCLUSIONS: Many current genome assemblers produced useful assemblies, containing a significant representation of their genes and overall genome structure. However, the high degree of variability between the entries suggests that there is still much room for improvement in the field of genome assembly and that approaches which work well in assembling the genome of one species may not necessarily work well for another.
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    ItemOpen Access
    Hybrid error correction and de novo assembly of single-molecule sequencing reads.
    (Nat Biotechnol, 2012-07-01) Koren, Sergey; Schatz, Michael C; Walenz, Brian P; Martin, Jeffrey; Howard, Jason T; Ganapathy, Ganeshkumar; Wang, Zhong; Rasko, David A; McCombie, W Richard; Jarvis, Erich D; Adam M Phillippy
    Single-molecule sequencing instruments can generate multikilobase sequences with the potential to greatly improve genome and transcriptome assembly. However, the error rates of single-molecule reads are high, which has limited their use thus far to resequencing bacteria. To address this limitation, we introduce a correction algorithm and assembly strategy that uses short, high-fidelity sequences to correct the error in single-molecule sequences. We demonstrate the utility of this approach on reads generated by a PacBio RS instrument from phage, prokaryotic and eukaryotic whole genomes, including the previously unsequenced genome of the parrot Melopsittacus undulatus, as well as for RNA-Seq reads of the corn (Zea mays) transcriptome. Our long-read correction achieves >99.9% base-call accuracy, leading to substantially better assemblies than current sequencing strategies: in the best example, the median contig size was quintupled relative to high-coverage, second-generation assemblies. Greater gains are predicted if read lengths continue to increase, including the prospect of single-contig bacterial chromosome assembly.