GenomeDescription-class
                        GenomeDescription objects
Seqinfo-class           Seqinfo objects
available.species       Returns a data.frame that lists the available
                        species strings and their taxonomy Ids.
fetchExtendedChromInfoFromUCSC
                        Fetching chromosomes info for some of the UCSC
                        genomes
mapGenomeBuilds         Mapping between UCSC and Ensembl Genome Builds
rankSeqlevels           Assign sequence IDs to sequence names
seqinfo                 Accessing/modifying sequence information
seqlevels-wrappers      Convenience wrappers to the seqlevels() getter
                        and setter
seqlevelsStyle          Conveniently rename the seqlevels of an object
                        according to a given style