To construct integrated secondary databases, primary source databases are classified into three categories.

Category Database
Disease UMLS(Unified Medical Language System)
Disease, Gene OMIM(Online Mendelian Inheritance In Man)
MorbidMap
GAD(Genetic Association Database)
NCBI
Gene HGNC(HUGO Gene Nomenclature Committee)
MitoDat(Universal Protein Resource)
Uniprot
Gene, SNP UCSC Genome Browser Database
SNP JSNP
ALFRED (Allele Frequency Database)
dbSNP


A schematic diagram of relational network between three secondary databases (genes, SNP, and disease)