[BioC] hs133phsentrezg metadata

[Nianhua Li]

> 	We know a probeset's genome location should be calculated from its
> probes' genome location, and it should be a range or multiple ranges
> under a small percentage of situations. However, it is hard to design a
> universal criteria to partition probes' location, as it depends on how
> wide one defines a range should be.
> 
> 	Probe '1007_s_at' exactly shows this problem. it seems the result from
> get("1007_s_at", hgu133plus2CHRLOC) only shows locations, instead of
> ranges. In addition, the location shows in the current annotation file
> is likely to be based on older version of genome assembly.

Hi, ManHong,

Just to clarify that the basic assumption of hgu133plus2 is each probeset maps
to one gene. Base on this assumption (even though it may not be true in
reality), the annotations of the genes are used to annotate the probesets. So,
get("1007_s_at", hgu133plus2CHRLOC) returns the *transcription start position*
of Entrez Gene 780 (discoidin domain receptor family, member 1, DDR1), not the
genome location of "1007_s_at". The information is obtained from UCSC Genome
Browser this August. I think it is hg18. 

thanks

nianhua