Analyzing big datasets of genomic sequences: fast and scalable collection of $k$-mer statistics

Abstract

Distributed approaches based on the MapReduce programming paradigm have started to be proposed in the Bioinformatics domain, due to the large amount of data produced by the next-generation sequencing techniques. However, the use of MapReduce and related Big Data technologies and frameworks (e.g., Apache Hadoop and Spark) does not necessarily produce satisfactory results, in terms of both efficiency and effectiveness. We discuss how the development of distributed and Big Data management technologies has affected the analysis of large datasets of biological sequences. Moreover, we show how the choice of different parameter configurations and the careful engineering of the software with respect to the specific framework under consideration may be crucial in order to achieve good performance, especially on very large amounts of data. We choose $k$-mers counting as a case study for our analysis, and Spark as the framework to implement FastKmer, a novel approach for the extraction of $k$-mer statistics from large collection of biological sequences, with arbitrary values of $k$.