SpectralTAD {SpectralTAD} | R Documentation

## Hierarchical Spectral Clustering of TADs

### Description

Hierarchical Spectral Clustering of TADs

### Usage

    SpectralTAD(cont_mat, chr, levels = 1, qual_filter = FALSE,
      z_clust = TRUE, eigenvalues = 2, min_size = 5,
      resolution = "auto", gap_threshold = 1, grange = FALSE)

### Arguments

`cont_mat` | Contact matrix in either sparse 3 column, n x n or n x (n+3) form where the first three columns are coordinates in BED format. If an x n matrix is used, the column names must correspond to the start point of the corresponding bin. Required.
`chr` | The chromosome of the contact matrix being analyzed. Required.
`levels` | The number of levels of the TAD hierarchy to be calculated. The default setting is 1.
`qual_filter` | Option to turn on quality filtering which removes TADs with negative silhouette scores (poorly organized TADs). Default is FALSE.
`z_clust` | Option to filter sub-TADs based on the z-score of their eigenvector gaps. Default is TRUE.
`eigenvalues` | The number of eigenvectors to be calculated. The default and suggested setting is 2.
`min_size` | The minimum allowable TAD size measured in bins. Default is 5.
`resolution` | The resolution of the contact matrix. If none selected, the resolution is estimated by taking the most common distance between bins. For n x (n+3) contact matrices, this value is automatically calculated from the first three columns.
`gap_threshold` | Corresponds to the percentage of zeros allowed before a column/row is removed from the analysis. 1=100%, .7 = 70%, etc. Default is 1.
`grange` | Parameter to determine whether the result should be a GRangeList object. Defaults to FALSE

### Details

Given a sparse 3 column, an n x n contact matrix, or n x (n+3) contact matrix, SpectralTAD returns a list of TAD coordinates in BED format. SpectralTAD works by using a sliding window that moves along the diagonal of the contact matrix. By default, we use the biologically relevant maximum TAD size of 2Mb and minimum size of 5 bins to determine the size of this window. Within each window, we calculate a Laplacian matrix and determine the location of TAD boundaries based on gaps between eigenvectors calculated from this matrix. The number of TADs in a given window is calculated by finding the number that maximizes the silhouette score. A hierarchy of TADs is created by iteratively applying the function to sub-TADs. The number of levels in each hierarchy is determined by the user.

### Value

A list where each entry is in BED format corresponding to the level of the hierarchy.

### Examples

    #Read in data
    data("rao_chr20_25_rep")
    #Find TADs
    spec_table <- SpectralTAD(rao_chr20_25_rep, chr= 'chr20')

[Package SpectralTAD version 1.4.0 Index]