decOM 0.0.21

decOM: Similarity-based microbial source tracking for contamination assessment of ancient oral samples using k-mer-based methods

decOM: Similarity-based microbial source tracking for contamination assessment of ancient oral samples using k-mer-based methods

decOM is a high-accuracy microbial source tracking method that is suitable for contamination quantification in paleogenomics, namely the analysis of collections of possibly contaminated ancient oral metagenomic data sets. In simple words, if you want to know how contaminated your ancient oral metagenomic sample is, this tool will help 🧹🦷

• System requirements
• Installation
• Before running decOM
• Test
• Output files
• Example
• Command-line options

System requirements

decOM has been developed and tested under a Linux environment and it only works in Linux-like systems. It requires certain packages/tools in order to be installed/used:

• miniconda3

Installation

Install decOM through conda:

git clone https://github.com/CamilaDuitama/decOM.git  
cd decOM  
conda env create -n decOM --file environment.yml  
conda deactivate
conda activate decOM  

To make the decOM command available, it is advised to include the absolute path of decOM in your PATH environment variable by adding the following line to your ~/.bashrc file:

export PATH=/absolute/path/to/decOM:${PATH}  

Before running decOM

BEFORE running decOM you must first download the folder decOM_sources.tar.gz and decompress it. You can either follow the link or use wget (it has to be installed in your computer first):

wget https://zenodo.org/record/6513520/files/decOM_sources.tar.gz  
tar -xf decOM_sources.tar.gz

If you did not use wget to download the matrix of sources and instead followed the link, make sure you know where the path to your file is and type it accordingly in the upcoming commands whenever p_sources is needed.

Test

One sink

You can test if decOM is working by using the aOral sample present in the test/sample/ folder, ex: SRR13355807.

decOM -s SRR13355807 -p_sources decOM_sources/ -k tests/sample/SRR13355807.fof -mem 10GB -t 5 

Note: The final memory allocated for each run of decOM will be your input in -mem times the number of cores (-t). In the previous run we used 10GB * 5 = 50 GB. It is recommended to run decOM with at least 10GB of memory and 1 core.

Several sinks

You can test if decOM with several sinks by using the files inside test/several_samples/ as follows:

decOM -p_sources decOM_sources/ -p_sinks tests/several_samples/sinks.txt -p_keys tests/several_samples/ -mem 10GB -t 5 

decOMrelies on DASK for parallelization. Once you start running decOMand the client is set, you can see the diagnostic dashboard to follow the process and better tune parameters such as -mem and -t, make sure you can connect to your local host and visualise it here: http://127.0.0.1:8787/status

Output files

decOM will output one .csv file with the k-mer counts and proportions, a folder with the vector representing the sample of interest, from now on called sink (s), and a barplot if indicated by the user.

decOM_output/  
├──decOM_output.csv 
├──result_plot_sinks.pdf 
├──result_plot_sinks.html 
├──{s}_vector/  

The decOM_output.csv file is a dataframe that contains one row per sink. The columns correspond to the raw number of k-mers per source environment, the running time per sink, the sink name and the proportions. The result for the one sample explained before should look like this:

Sediment/Soil	Skin	aOral	mOral	Unknown	Running time (s)	Sink	p_Sediment/Soil	p_Skin	p_aOral	p_mOral	p_Unknown
182	281	197859	37023	334	196.7268	SRR13355807	0.0772	0.1192	83.9527	15.7091	0.1417

The result_plot_sinks.pdfand result_plot_sinks.htmlare static and interactive plots (respectively) for the proportions of source environments per sink. The {s}_vector/ folder is the output of kmtricks filter + kmtricks aggregate.

Example

You can use as input your fastq/fasta file from your own experiment, you can download an ancient oral sample of interest from the AncientMetagenomeDir or from the SRA.
The users of decOM can represent their own metagenomic sample as a presence/absence vector of k-mers using kmtricks. This sink can be compared against the collection of sources we have put together.

Once you have downloaded the folder with the matrix of sources and the fastq file(s) of your sink(s), you have to create a key.fof file per sink.
The key.fof has one line of text depending on your type of data:

-Single-end:
s : path/to/file/s_1.fastq.gz

-Paired-end :
s : path/to/file/s_1.fastq.gz; path/to/file/s_2.fastq.gz

Note: As decOM relies on kmtricks, you might use a FASTA or FASTQ format, gzipped or not, which means you have to change the key.fof file accordingly.

Since you now have the fasta/fastq file of your sink, the folder with the matrix of sources and the key file, simply run decOM as follows:

Single sink

decOM -s {SINK} -p_sources decOM_sources/ -k {KEY.FOF} -mem {MEMORY} -t {THREADS}

Several sinks

If you want to assess the contamination of several sinks, you need one key.fof file per sink, and they must be inside the folder p_sources

decOM -p_sinks {PATH_SINKS} -p_sources decOM_sources/ -p_keys {PATH_KEYS} -mem {MEMORY} -t {THREADS}

Command line options

usage: decOM [-h] (-s SINK | -p_sinks PATH_SINKS) -p_sources PATH_SOURCES (-k KEY | -p_keys PATH_KEYS) -mem MEMORY -t THREADS [-o OUTPUT]
[-p PLOT] [-V] [-v]

Microbial source tracking for contamination assessment of ancient oral samples using k-mer-based methods


Arguments:

-h, --help  
show this help message and exit

-s SINK, --sink SINK  
Write down the name of your sink. It must be the same as the first element of key.fof. When this argument is set,-k/--key must be defined too

-p_sinks PATH_SINKS, --path_sinks PATH_SINKS 
.txt file with a list of sinks limited by a newline (\n). When this argument is set, -p_keys/--path_keys must be defined too.

-p_sources PATH_SOURCES, --path_sources PATH_SOURCES
Path to folder downloaded from https://zenodo.org/record/6513520/files/decOM_sources.tar.gz

-k KEY, --key KEY 
Filtering key (a kmtricks fof with only one sample). When this argument is set, -s/--sink must be defined too.

-p_keys PATH_KEYS, --path_keys PATH_KEYS
Path to folder with filtering keys (a kmtricks fof with only one sample).You should have as many .fof files as sinks.When this argument is set, -p_sinks/--path_sinks must be defined too.

-mem MEMORY, --memory MEMORY
Write down how much memory you want to use for this process. Ex: 10GB

-t THREADS, --threads THREADS
Number of threads to use. Ex: 5

-o OUTPUT, --output OUTPUT
Path to output folder, where you want decOM to write the results. Folder must not exist, it won't be overwritten.

-p PLOT, --plot PLOT  True if you want a plot (in pdf and html format) with the source proportions of the sink, else False

-V, --version Show version number and exit

-v, --verbose Verbose output