What it does
This tool converts every MAF block to a set of genomic intervals describing the position of that alignment block within a corresponding genome. Sequences from aligning species are also included in the output.
The interface for this tool contains several options:
- MAF file to convert. Choose multiple alignments from history to be converted to BED format.
- Choose species. Choose additional species from the alignment to be included in the output
- Exclude blocks which have a species missing. if an alignment block does not contain any one of the species found in the alignment set and this option is set to exclude blocks with missing species, then coordinates of such a block will not be included in the output (see Example 2 below).
- Remove Gap characters from sequences. Gaps can be removed from sequences before they are output.
Example 1: Include only reference genome (hg18 in this case) and include blocks with missing species:
For the following alignment:
a score=68686.000000 s hg18.chr20 56827368 75 + 62435964 GACAGGGTGCATCTGGGAGGG---CCTGCCGGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- s panTro2.chr20 56528685 75 + 62293572 GACAGGGTGCATCTGAGAGGG---CCTGCCAGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- s rheMac2.chr10 89144112 69 - 94855758 GACAGGGTGCATCTGAGAGGG---CCTGCTGGGCCTTTG-TTCAAAACTAGATATGCCCCAACTCCAATTCTA------- s mm8.chr2 173910832 61 + 181976762 AGAAGGATCCACCT------------TGCTGGGCCTCTGCTCCAGCAAGACCCACCTCCCAACTCAAATGCCC------- s canFam2.chr24 46551822 67 + 50763139 CG------GCGTCTGTAAGGGGCCACCGCCCGGCCTGTG-CTCAAAGCTACAAATGACTCAACTCCCAACCGA------C a score=10289.000000 s hg18.chr20 56827443 37 + 62435964 ATGTGCAGAAAATGTGATACAGAAACCTGCAGAGCAG s panTro2.chr20 56528760 37 + 62293572 ATGTGCAGAAAATGTGATACAGAAACCTGCAGAGCAG s rheMac2.chr10 89144181 37 - 94855758 ATGTGCGGAAAATGTGATACAGAAACCTGCAGAGCAG
the tool will create a single history item containing the following (note the name field is numbered iteratively: hg18_0_0, hg18_1_0 etc. where the first number is the block number and the second number is the iteration through the block (if a species appears twice in a block, that interval will be repeated) and sequences for each species are included in the order specified in the header: the field is left empty when no sequence is available for that species):
#chrom start end strand score name canFam2 hg18 mm8 panTro2 rheMac2 chr20 56827368 56827443 + 68686.0 hg18_0_0 CG------GCGTCTGTAAGGGGCCACCGCCCGGCCTGTG-CTCAAAGCTACAAATGACTCAACTCCCAACCGA------C GACAGGGTGCATCTGGGAGGG---CCTGCCGGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- AGAAGGATCCACCT------------TGCTGGGCCTCTGCTCCAGCAAGACCCACCTCCCAACTCAAATGCCC------- GACAGGGTGCATCTGAGAGGG---CCTGCCAGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- GACAGGGTGCATCTGAGAGGG---CCTGCTGGGCCTTTG-TTCAAAACTAGATATGCCCCAACTCCAATTCTA------- chr20 56827443 56827480 + 10289.0 hg18_1_0 ATGTGCAGAAAATGTGATACAGAAACCTGCAGAGCAG ATGTGCAGAAAATGTGATACAGAAACCTGCAGAGCAG ATGTGCGGAAAATGTGATACAGAAACCTGCAGAGCAG
Example 2: Include hg18 and mm8 and exclude blocks with missing species:
For the following alignment:
a score=68686.000000 s hg18.chr20 56827368 75 + 62435964 GACAGGGTGCATCTGGGAGGG---CCTGCCGGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- s panTro2.chr20 56528685 75 + 62293572 GACAGGGTGCATCTGAGAGGG---CCTGCCAGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- s rheMac2.chr10 89144112 69 - 94855758 GACAGGGTGCATCTGAGAGGG---CCTGCTGGGCCTTTG-TTCAAAACTAGATATGCCCCAACTCCAATTCTA------- s mm8.chr2 173910832 61 + 181976762 AGAAGGATCCACCT------------TGCTGGGCCTCTGCTCCAGCAAGACCCACCTCCCAACTCAAATGCCC------- s canFam2.chr24 46551822 67 + 50763139 CG------GCGTCTGTAAGGGGCCACCGCCCGGCCTGTG-CTCAAAGCTACAAATGACTCAACTCCCAACCGA------C a score=10289.000000 s hg18.chr20 56827443 37 + 62435964 ATGTGCAGAAAATGTGATACAGAAACCTGCAGAGCAG s panTro2.chr20 56528760 37 + 62293572 ATGTGCAGAAAATGTGATACAGAAACCTGCAGAGCAG s rheMac2.chr10 89144181 37 - 94855758 ATGTGCGGAAAATGTGATACAGAAACCTGCAGAGCAG
the tool will create two history items (one for hg18 and one for mm8) containing the following (note that both history items contain only one line describing the first alignment block. The second MAF block is not included in the output because it does not contain mm8):
History item 1 (for hg18):
#chrom start end strand score name canFam2 hg18 mm8 panTro2 rheMac2 chr20 56827368 56827443 + 68686.0 hg18_0_0 CG------GCGTCTGTAAGGGGCCACCGCCCGGCCTGTG-CTCAAAGCTACAAATGACTCAACTCCCAACCGA------C GACAGGGTGCATCTGGGAGGG---CCTGCCGGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- AGAAGGATCCACCT------------TGCTGGGCCTCTGCTCCAGCAAGACCCACCTCCCAACTCAAATGCCC------- GACAGGGTGCATCTGAGAGGG---CCTGCCAGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- GACAGGGTGCATCTGAGAGGG---CCTGCTGGGCCTTTG-TTCAAAACTAGATATGCCCCAACTCCAATTCTA-------
History item 2 (for mm8):
#chrom start end strand score name canFam2 hg18 mm8 panTro2 rheMac2 chr2 173910832 173910893 + 68686.0 mm8_0_0 CG------GCGTCTGTAAGGGGCCACCGCCCGGCCTGTG-CTCAAAGCTACAAATGACTCAACTCCCAACCGA------C GACAGGGTGCATCTGGGAGGG---CCTGCCGGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- AGAAGGATCCACCT------------TGCTGGGCCTCTGCTCCAGCAAGACCCACCTCCCAACTCAAATGCCC------- GACAGGGTGCATCTGAGAGGG---CCTGCCAGGCCTTTA-TTCAACACTAGATACGCCCCATCTCCAATTCTAATGGAC- GACAGGGTGCATCTGAGAGGG---CCTGCTGGGCCTTTG-TTCAAAACTAGATATGCCCCAACTCCAATTCTA-------
About formats
MAF format multiple alignment format file. This format stores multiple alignments at the DNA level between entire genomes.
- The .maf format is line-oriented. Each multiple alignment ends with a blank line.
- Each sequence in an alignment is on a single line.
- Lines starting with # are considered to be comments.
- Each multiple alignment is in a separate paragraph that begins with an "a" line and contains an "s" line for each sequence in the multiple alignment.
- Some MAF files may contain two optional line types:
- An "i" line containing information about what is in the aligned species DNA before and after the immediately preceding "s" line;
- An "e" line containing information about the size of the gap between the alignments that span the current block.