CALQ: compression of quality values of aligned sequencing data

Motivation: Recent advancements in high-throughput sequencing technology have led to a rapid growth of genomic data. Several lossless compression schemes have been proposed for the coding of such data present in the form of raw FASTQ files and aligned SAM/BAM files. However, due to their high entrop...

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Detalles Bibliográficos
Autores: Hernaez-Arrazola, M. (Mikel)|||/items/954a4ee7-b04c-4dc5-9bfc-7a48332c7e5a, Voges, J. (Jan)|||/items/f6b015c2-50f6-405e-8525-8693b89c3816, Ostermann, J. (Jörn)|||/items/07cadfa0-d925-4691-a4f9-b4a7b3763d5d
Tipo de recurso: artículo
Fecha de publicación:2018
País:España
Institución:Universidad de Navarra
Repositorio:Dadun. Depósito Académico Digital de la Universidad de Navarra
Idioma:inglés
OAI Identifier:oai:dadun.unav.edu:10171/113611
Acceso en línea:https://hdl.handle.net/10171/113611
Access Level:acceso abierto
Palabra clave:CALQ
Compression
Aligned sequencing data
Quality values
Descripción
Sumario:Motivation: Recent advancements in high-throughput sequencing technology have led to a rapid growth of genomic data. Several lossless compression schemes have been proposed for the coding of such data present in the form of raw FASTQ files and aligned SAM/BAM files. However, due to their high entropy, losslessly compressed quality values account for about 80% of the size of compressed files. For the quality values, we present a novel lossy compression scheme named CALQ. By controlling the coarseness of quality value quantization with a statistical genotyping model, we minimize the impact of the introduced distortion on downstream analyses. Results: We analyze the performance of several lossy compressors for quality values in terms of trade-off between the achieved compressed size (in bits per quality value) and the Precision and Recall achieved after running a variant calling pipeline over sequencing data of the well-known NA12878 individual. By compressing and reconstructing quality values with CALQ, we observe a better average variant calling performance than with the original data while achieving a size reduction of about one order of magnitude with respect to the state-of-the-art lossless compressors. Furthermore, we show that CALQ performs as good as or better than the state-of-the-art lossy compressors in terms of variant calling Recall and Precision for most of the analyzed datasets.