In this package, we provide four algorithms to infer the 3D structure of the genome: MDS, NMDS, PM1, PM2. For all methods, chromosomes are represented as beads on a string, at a given resolution. All are installed as a standalone program: pastis-mds, pastis-nmds, pastis-pm1, pastis-pm2.
We provide a sample interaction count matrix of the first 5 chromosomes and
configuration file config.ini. To run the example, edit the two options
binary_mds (respectively binary_pm) to the path where you have
installed MDS_all (respectively PM_all).
[all]
resolution: 10000
output_name: structure.pdb
counts: data/counts.matrix
To run the code, simply call the program of your choice, and the repository containing the configuration file as argument. From the root of the repository, to run the MDS:
pastis-mds example
A bunch of files, necessary for the optimization are written in the same
folder as the optimization, including the results of the optimization:
MDS.structure and MDS.structure.pdb. The txt file contains the
array of coordinates while the pdb contains a smoothed interpolation of
the structure for visualization purposes.
Running the algorithms on your own structure, and your own organism will require a bit more work.
The interaction count matrix needs to be saved as a numpy array, in the folder of your choice. Numpy arrays are memory-efficient container that provides fast numerical operations: the ideal structure to work efficiently with matrices in Python. For efficient and accurate
The organism structure (chromosomes lengths of the organism) have to be
specified in a text file, one chromosomes length per base pair. See
example/files/budding_yeast_structure for an example.
Then, create the configuration file, specifying the resolution on which to run the algorithm: the resolution of the interaction counts matrix, the chromosomes lengths and the resolution should be coherent.