\name{org.Xl.egUNIGENE}
\alias{org.Xl.egUNIGENE}
\alias{org.Xl.egUNIGENE2EG}
\title{Map between Entrez Gene Identifiers and UniGene cluster identifiers}
\description{
   org.Xl.egUNIGENE is an R object that provides mappings between
   entrez gene identifiers and UniGene identifiers.
}
\details{
  Each entrez gene identifier is mapped to a UniGene identifier. An \code{NA} is
  reported if the entrez gene identifier cannot be mapped to UniGene at this time. 

  A UniGene identifier represents a cluster of sequences of a gene. Using
  UniGene identifiers one can query the UniGene database for information about
  the sequences.  
  
  Mappings were based on data provided by: Entrez Gene  
  ftp://ftp.ncbi.nlm.nih.gov/gene/DATA  
  With a date stamp from the source of: 2010-Mar1

}
\references{
  \url{http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene}
}
\examples{
        x <- org.Xl.egUNIGENE
        # Get the Unigene identifiers that are mapped to an entrez gene id
        mapped_genes <- mappedkeys(x)
        # Convert to a list
        xx <- as.list(x[mapped_genes])
        if(length(xx) > 0) {
          # Get the UNIGENE for the first five genes
          xx[1:5]
          # Get the first one
          xx[[1]]
        }
        # For the reverse map:
        x <- org.Xl.egUNIGENE2EG
        # Get the entrez gene identifiers that are mapped to a Unigene id
        mapped_genes <- mappedkeys(x)
        # Convert to a list
        xx <- as.list(x[mapped_genes])
        if(length(xx) > 0) {
          # Get the entrez gene for the first five genes
          xx[1:5]
          # Get the first one
          xx[[1]]
        }
}

\keyword{datasets}