Quote:
Originally Posted by sqcrft
check this: http://user.list.galaxyproject.org/a...td4366680.html
Jeremy,
This is not strictly correct. Tophat/bowtie don’t report mapping quality values that are as meaningful as BWA, but there is some information in the mapping quality values tophat reports. Tophat yields 4 distinct values for its mapping quality values (you can do a “unique” count on the mapping quality field of any SAM file from tophat to verify this):
255 = unique mapping
3 = maps to 2 locations in the target
2 = maps to 3 locations
1 = maps to 4-9 locations
0 = maps to 10 or more locations. |
This actually does not seem to hold upon checking (or at least not anymore). In Tophat 1.4.1, there is no mapping quality of 2. I've looked at a large number of BAM files and it seems that the qualities are as follows:
255 = unique mapping
3 = maps to 2 locations in the target
1 = maps to 3-4 locations
0 = maps to 5 or more locations (up to the number defined in "--max-multihits").
cheers