CrossMap

CrossMap is versatile tool to convert genome coordinates or annotation files between genome assemblies. It supports mostly commonly used file types, including BAM, BED,BigWig, GFF, GTF, SAM, Wiggle, and VCF formats. For large plain text file types, such as BED, GFF, GTF and VCF, reading from remote servers and file compression are supported.

CrossMap region

Unlike the "CrossMap bed" function which splits big genomic regions, "CrossMap region" tries to convert the big genomic region as a whole.

BED

BED format file must have at least 3 columns (chrom, start, end) and no more than 12 columns. BED format: http://genome.ucsc.edu/FAQ/FAQformat.html#format1

A BED (Browser Extensible Data) file is a tab-delimited text file describing genome regions or gene annotations. It is the standard file format used by UCSC. It consists of one line per feature, each containing 3-12 columns. CrossMap converts BED files with less than 12 columns to a different assembly by updating the chromosome and genome coordinates only; all other columns remain unchanged. Regions from old assembly mapping to multiple locations to the new assembly will be split. For 12-columns BED files, all columns will be updated accordingly except the 4th column (name of bed line), 5th column (score value) and 9th column (RGB value describing the display color). 12-column BED files usually define multiple blocks (eg. exon); if any of the exons fails to map to a new assembly, the whole BED line is skipped.

Notes:

1. For BED-like formats mentioned above, CrossMap only updates “chrom (1st column)”, “start (2nd column) ”, “end (3rd column) ” and “strand” (if any). All other columns will keep AS-IS.
2. Lines starting with ‘#’, ‘browser’, ‘track’ will be skipped.
3. Lines will less than 3 columns will be skipped.
4. 2nd-column and 3-column must be integer, otherwise skipped.
5. “+” strand is assumed if no strand information was found.
6. For standard BED format (12 columns). If any of the defined exon blocks cannot be uniquely mapped to target assembly, the whole entry will be skipped.
7. If input region cannot be consecutively mapped target assembly, it will be split.
8. *.unmap file contains regions that cannot be unambiguously converted.