Orthologous MAtrix

{{infobox biodatabase

|title = OMA

|logo =File:Database.png

|description =orthology inference among 1000 complete genomes.

|scope =

|organism =

|center =

|laboratory = ETH Zurich

|author = Christophe Dessimoz
Adrian Schneider
Adrian Altenhoff
Gaston H. Gonnet

|citation = Altenhoff et al.

|released =2004

|standard =

|format =

|url = {{URL|omabrowser.org}}

|download = http://omabrowser.org/All/download.html

|webservice =[http://omabrowser.org/omabrowser.wsdl wsdl]

|sql =

|sparql =

|webapp =

|standalone =

|license =

|versioning =

|frequency = 2 releases per year

|curation =

|bookmark =

|version=

}}OMA (Orthologous MAtrix) is a database of orthologs extracted from available complete genomes.{{cite journal |last=Altenhoff|first=Adrian M|author2=Schneider Adrian |author3=Gonnet Gaston H |author4=Dessimoz Christophe |date=Jan 2011|title=OMA 2011: orthology inference among 1000 complete genomes|journal = Nucleic Acids Res.|volume=39|issue=Database issue|pages=D289-94|location = England| pmid = 21113020|doi = 10.1093/nar/gkq1238| pmc = 3013747 }}{{cite journal|last1=Altenhoff|first1=Adrian M|last2=Glover|first2=Natasha M|last3=Train|first3=Clément-Marie|last4=Kaleb|first4=Klara|last5=Warwick Vesztrocy|first5=Alex|last6=Dylus|first6=David|last7=de Farias|first7=Tarcisio M|last8=Zile|first8=Karina|last9=Stevenson|first9=Charles|last10=Long|first10=Jiao|last11=Redestig|first11=Henning|last12=Gonnet|first12=Gaston H|last13=Dessimoz|first13=Christophe|title=The OMA orthology database in 2018: retrieving evolutionary relationships among all domains of life through richer web and programmatic interfaces|journal=Nucleic Acids Research|volume=46|issue=D1|year=2018|pages=D477–D485|issn=0305-1048|doi=10.1093/nar/gkx1019|pmid= 29106550 |pmc=5753216}} The orthology predictions of OMA are available in several forms:

• OMA Pairs: for a given gene, a list of predicted orthologs in other species is provided.
• OMA Groups: a set of genes across different species which are all orthologous.
• OMA Hierarchical Groups: the set of all genes that have evolved from a single ancestral gene in a given taxonomic range.
• OMA Genome Pair view: the list of all predicted orthologs between two species.