Dear all,

my name is Carsten Raabe and I am working at the institute of 
experimental Pathology in Münster, Germany.

I do have a hard time understanding what the columns in the 
wgEncodeCshlShortRnaSeqGm12878CytosolShortTransfrags.shortFrags file 
stand for.
I tried to go via the table browser in order to see the table option 
offered and I assume these would the same fields as in the file 
specified above. I do have a bunch question on what the specific columns 
stand for. Please find my doubts in detail below...

bin
chromReference sequence chromosome or scaffold
chromStartStart position in chromosome
chromEndEnd position in chromosome
nameName of item
scoreScore from 0-1000 >>>>> what does the score indicate
strand    + or -
length >>>>> Difference between end and start position ??
numUnique >>>> unique reads in the contig ?
numReads >>>> all reads forming the contig ?
minSeqCount >>>> what is the difference between seq and read ?
maxSeqCount
aveSeqCount
firstSeqCount >>>> Besides the question above I am not clear on what 
does "first" indicate here.
medSeqCount
thirdSeqCount >>>> The same question as with  "first" in the above row.
minReadCount >>>> Again what would be the difference between read and seq.
maxReadCount
aveReadCount
firstReadCount
medReadCount
thirdReadCount what would the meaning of third here.
numRegions >>>> I assume it refers to significant region within the 
contig, how would these (>>> regions) be defined??
regStart
regLength
seqCount
regCount
sumCount


I checked the mailing list and didn't find a lot of information on these 
questions above. I furthermore saw the description of tranfrags on the 
browser page

"Small RNA reads were assembled into "Transfrags" by merging reads with 
one or more overlapping nucleotides. In order to minimize ambiguity from 
reads that have the potential to map to multiple genomic loci, only the 
uniquely mapping reads were used to generate Transfrags. The BED6+ 
format of the transfrag files are created from "intervals-to-contigs" 
Galaxy tool written by Assaf Gordon in the Hannon lab at CSHL. A 
complete description of the columns in this format can be found here. 
The Transfrags view includes all transfrags before filtering."


However, the BED6 link doesn't work. I am also confused with regards to 
the term unique if only unique reads (>>> unique in position, as stated 
in the citation) were utilized to form the corresponding frags, why is 
the number of numUnique not always identical to numReads.


I am sorry for troubling you a lot with all these questions, however I 
wouldn't know whom else to ask.

Keep up the beautiful work.

Cheers,

Carsten
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