I want to use gene tables from UCSC to retrieve genes, exons and introns separately. What puzzles me is that exon frames contains values ranging from -1 to 2, so in total 4 'different' registers. For instance:
NM_001308203 (...) -1,0,1,2,0,0,1,0,1,2,1,1,1,0,1,1,2,2,0,2,1,1
I've skipped some of the fields due to improved readability.
If our exon localization on the chromosome is let's say [451:987] with frame 1 it's obvious it will be exonStart:exonEnd 452:987. But what happens if exon frame is -1? It will be then 450:987? It seems so, but then why isn't it then in the table - exonStart:exonEnd 450:987 with exon frame 0?
I guess it's quite simple question but I just want to make sure I understand completely their denominations.
Thank you in advance!