Table 1.

Taxonomic conservation groups. Taxonomic conservation groups are assigned manually from a controlled set of terms at the kingdom/domain level. A gene may be annotated to multiple different orthologous groups. Taxon restrictions are recorded for where orthologs have not been identified outside of the noted taxa (fungi or eukaryotes). The absence of an ortholog in the S. cerevisiae reference sequence is also recorded. Copy number conservation is also documented, for example whether the gene is conserved one-to-one or whether orthologs cannot be distinguished. In some cases, faster evolving duplicates may be observed—this is where a copy of a gene appears to evolve faster than another copy of the gene

Orthologous groups	Conserved in archaea Conserved in bacteria Conserved in eukaryotes Conserved in fungi Conserved in metazoa Conserved in vertebrates Schizosaccharomyces specific Schizosaccharomyces pombe specific
Taxon restrictions	Conserved in fungi only Conserved in eukaryotes only
Others	No apparent S.cerevisiae ortholog Predominantly single copy (one-to-one) Orthologs cannot be distinguished Faster evolving duplicate