ZEC: Mining statistically-solid k-mers for accurate NGS error correction

The paper has been published in BMC Genomic at https://rdcu.be/be2c5

ZEC is developed based on the BLESS, which is developed by ESCAD Group, Computational Comparative Genomics Lab, and IMPACT Group in Univsersity of Illinois at Urbana-Champaign

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System Requirements

Compiling ZEC requires MPI libraries. The latest version of ZEC was tested with GCC 4.9.2, MPICH 3.1.3 (or OpenMPI 1.8.2).

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Dependency

MPI: tested using MPICH 3.1.3 and OpenMPI 1.8.4

(Included dependent libraries)
Boost library (http://www.boost.org)
Google sparsehash (https://code.google.com/p/sparsehash)
klib (https://github.com/attractivechaos/klib)
KMC (http://sun.aei.polsl.pl/REFRESH/index.php?page=projects&project=kmc&subpage=about)
murmurhash3 (https://code.google.com/p/smhasher)
zlib (http://zlib.net)
pigz (http://zlib.net/pigz)

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How to Install ZEC

Type make.

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How to Run ZEC

Single-end reads or merged paired-end reads

./zec -read <fastq> -prefix <output prefix> -kmerlength <k-mer length>
<fastq> : fastq file name
<output prefix>: <output directory name>/<file prefix>
<k-mer length> : k-mer length (odd number)

Paired-end reads

./zec -read1 <forward fastq> -read2 <reverse fastq> -prefix <output prefix> -kmerlength <k-mer length>
<forward fastq>: first read file of a paired-end fastq file
<reverse fastq>: second read file of a paired-end fastq file
<output prefix>: <output directory name>/<file prefix>
<k-mer length> : k-mer length (odd number)

Run zec with no option to see the entire options.

Running ZEC on multiple nodes using MPI
Launch single process on a node and bind the processes to their nodes Ex) MPICH 3.1.3 Hydra Version

mpirun -ppn 1 -bind-to board ./zec <options>

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Choosing k-mer length

Our empirical analysis shows that the k value that satisfies the following two conditions usually generates the results close to the best one:

1. Ns / 4^k <= 0.0001 where Ns represents the number of unique solid k-mers (ZEC reports Ns).
2. Number of corrected bases becomes the maximum at the chosen k value, which means you need to increase k as long as the number of corrected reads increases.

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Bug Reports:

Dr. Zhao <s080011 AT e.ntu.edu.sg>