On Jul 17, 2009, at 11:15 AM, C. Titus Brown wrote:
> "Position mod 3" does work for forward frames.  For RC frames, it  
> may be
> as simple as doing a transform -- I think that -1 -> - (+1), while  
> -2 ->
> -(+3) and -3 -> -(+2).

A big simplification in Pygr is that all coordinates (negative as well  
as positive) are given relative to the start of the positive  
coordinate system,

i.e. -(seq[10:50]) == (-seq)[-50:-10]
the coordinates for the first interval are (10,50) and for the second  
(-50,-10)

TranslationDB calculates the positive frame as abs(start) % 3.  If  
start<0 then the frame is negative.  Thus frame "-0" is just the  
translation of the reverse complement of frame "0".  Rather than  
thinking of this as "-0", think of this as two separate variables, one  
specifying the frame (0, 1, 2) and the other specifying the strand (+  
or -).

-- Chris


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups 
"pygr-dev" group.
To post to this group, send email to [email protected]
To unsubscribe from this group, send email to 
[email protected]
For more options, visit this group at 
http://groups.google.com/group/pygr-dev?hl=en
-~----------~----~----~----~------~----~------~--~---

Reply via email to