Considerable lncRNA databases have been reported, but no one systematically collects orthologues of GENCODE-annotated human and mouse lncRNAs in multiple mammalian clades and species. A systematic collection of orthologous lncRNAs in multiple species is essential for comparative and evolutionary lncRNA analysis and helpful for uncovering whether the functions of an lncRNA show species specific variations.

LongMan is an lncRNA database currently dedicated to systematically collecting GENCODE-annotated human and mouse lncRNAs and orthologues of GENCODE-annotated human and mouse lncRNAs in multiple representative mammals, including the marsupial opossum and the monotreme platypus. Currently LongMan has a plain user interface, but provides strong database search functions comparable to those in popular databases. "Search orthologues of human lncRNA", "Blast", and especially "Search orthologues upon multi-conditions", can flexibly produce many search results.

The most important function of lncRNAs is to recruit DNA methylation and histone modification enzymes to specific genomic sites to regulate gene expression epigenetically. Thus, the roles of lncRNAs vary in different cellular contexts, depending on where and when they bind to genomic sites. In addition to database search, an important function of LongMan is to support a database-based large-scale or genome-wide lncRNA/DNA binding prediction. Now, we have integrated LongTarget into LongMan to implement a seamless pipeline to implement this function. For example, by choosing "Species=human" and "Chr=all" in "Search orthologues upon multi-conditions" the database search returns the 13562 GENCODE-annotated human lncRNAs, and from this point a genome-scale prediction of the 13562 lncRNAs’ DNA binding sites in a genomic region can be triggered easily. More