Alta-Cyclic: a self-optimizing base caller for next-generation sequencing

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Next-generation sequencing is limited to short read lengths and by high error rates. We systematically analyzed sources of noise in the Illumina Genome Analyzer that contribute to these high error rates and developed a base caller, Alta-Cyclic, that uses machine learning to compensate for noise factors. Alta-Cyclic substantially improved the number of accurate reads for sequencing runs up to 78 bases and reduced systematic biases, facilitating confident identification of sequence variants.

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Figure 1: Schematic representation of main Illumina noise factors.
Figure 2: Alta-Cyclic base caller data flow.
Figure 3: Comparison between Alta-Cyclic and Illumina base caller on the GAII platform.


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We thank M. Rooks, E. Hodges, K. Fejes-Toth and C. Malone for help in preparing libraries. We thank M. Regulski, D. Rebolini and L. Cardone for Illumina sequencing, and T. Heywood for assistance with cluster computing. F. Chen, D. Hillman and J. Eisen (Lawrence Berkeley National Lab) provided the Tetrahymena micronuclear library. Y.E. is a Goldberg-Lindsay Fellow of the Watson School of Biological Sciences. P.P.M. is a Crick-Clay Professor. G.J.H. is an investigator of the Howard Hughes Medical Institute. This work was supported by grants from the US National Institute of Health, the National Science Foundation and the Stanley Foundation.

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Correspondence to Gregory J Hannon.

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Supplementary Figures 1–7, Supplementary Table 1, Supplementary Data, Supplementary Methods (PDF 941 kb)

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