[BioC] annotation on mouse4302

[Mayte Suarez-Farinas]

Hi

I am using mouse4302 chips and my biology counterpart found some odds  
annotations,
for a non negligible number of gene the symbols produced by  
Bioconductor and affymetrix web  site
are very different (meaning they are even not synonyms), usually what  
it happens is that
the genes are next to each other in the genome (If you look at them  
in USCS genome browser)
An example
probeset: 1442021_at:

Bioconductor annotation
entrez id: 225651        symbol:Mppe1
refseq: NM_172630    NP_766218    XM_001001173 XM_001001180  
XM_001001193 XM_001001206 XM_001001219 XP_001001173
  XP_001001180 XP_001001193 XP_001001206 XP_001001219

Affy annotation
entrez id:  14680          symbol: Gnal
refseq: NM_010307 NM_177137

I guess my question is how is the mapping done, so that it results in  
such a difference...and which one
is better. For what reason are those annotation at odds with  
affymetrix. Which at should believe better ?


Thanks in advance

Mayte