ChainX

ChainX is a tool that computes co-linear chaining costs between an input target and query sequences. It supports global and semi-global comparison modes. A unique aspect of ChainX is that it supports anchor overlaps and gap costs, and produces optimal chaining cost. For a pair of sequences, (i) computing chaining chaining cost can be orders of magnitude faster than computing edit distance, and (ii) chaining costs and edit distances correlate well with each other. As a result, ChainX can serve as a faster alternative to computing edit distance. More details about theoretical and practical efficacy of ChainX are available in our preprint.

Dependencies / External libraries

ChainX repository uses many third-party libraries. These are separately provided in ext folder.

• A C++ compiler with c++11 support, e.g., GNU g++ (version 5+)
• essaMEM
• libdivsufsort
• MUMmer
• edlib
• clipp
• cxx-prettyprint
• kseq

Installation

git clone https://github.com/AT-CG/ChainX.git
cd ChainX
make

Usage

SYNOPSIS
        ./chainX [-l <length>] [-a (MEM|MUM)] [--all2all] [--naive] -m (g|sg) -q <qpath> -t <tpath>

OPTIONS
        <length>    minimum anchor match length (default = 20)
        MEM|MUM     anchor type (default = MUM)
        --all2all   output all to all global distances among query sequences in phylip format
        --naive     use slow 2d dynamic programming algorithm for correctness check
        g|sg        distance function (e.g., global or semi-global)
        <qpath>     query sequences in fasta or fastq format
        <tpath>     target sequence in fasta format

Example

Test data can be accessed from data folder. Here is an example run.

$ ./chainX -m g -q data/time_global/mutated_80_perc.fasta -t data/time_global/Chromosome_2890043_3890042_0.fasta
INFO, chainx::parseandSave, target sequence file = data/time_global/Chromosome_2890043_3890042_0.fasta
INFO, chainx::parseandSave, query sequences file = data/time_global/mutated_80_perc.fasta
INFO, chainx::parseandSave, mode = g
INFO, chainx::parseandSave, anchor : minimim length = 20, type = MUM
INFO, chainx::main, read 1 queries, 999760 residues
INFO, chainx::main, read target, 1000000 residues
INFO, chainx::main, timer set
INFO, chainx::main, suffix array computed in 0.162169 seconds
INFO, chainx::main, timer reset
INFO, chainx::main, count of anchors (including dummy) = 2964, average length = 24.0651
INFO, chainx::main, query #0 (999760 residues), distance = 939635
INFO, chainx::main, distance computation finished (0.197675 seconds elapsed)

Publications

• Chirag Jain, Daniel Gibney and Sharma Thankachan. "Co-linear chaining with overlaps and gap costs". RECOMB 2022.