\name{org.Bt.egCHRLOC}
\alias{org.Bt.egCHRLOC}
\alias{org.Bt.egCHRLOCEND}
\title{Entrez Gene IDs to Chromosomal Location}
\description{
  org.Bt.egCHRLOC is an R object that maps entrez gene identifiers to the
  starting position of the gene. The position of a gene is
  measured as the number of base pairs.

  The CHRLOCEND mapping is the same as the CHRLOC mapping except that it
  specifies the ending base of a gene instead of the start.
}
\details{
  Each entrez gene identifier maps to a named vector of chromosomal locations,
  where the name indicates the chromosome. 
  
  Chromosomal locations on both the sense and antisense strands are
  measured as the number of base pairs from the p (5' end of the sense
  strand) to q (3' end of the sense strand) arms. Chromosomal locations on the
  antisense strand have a leading "-" sign (e. g. -1234567). 

  Since some genes have multiple start sites, this field can map to
  multiple locations.
 
  Mappings were based on data provided by: UCSC Genome Bioinformatics (Bos taurus)  
  ftp://hgdownload.cse.ucsc.edu/goldenPath/bosTau4  
  With a date stamp from the source of: 2009-Jul5
  
}
\examples{
        x <- org.Bt.egCHRLOC
        # Get the entrez gene identifiers that are mapped to chromosome locations
        mapped_genes <- mappedkeys(x)
        # Convert to a list
        xx <- as.list(x[mapped_genes])
        if(length(xx) > 0) {
          # Get the CHRLOC for the first five genes
          xx[1:5]
          # Get the first one
          xx[[1]]
        }
}
\keyword{datasets}