Table 1. Proportions of S.cerevisiae, S.pombe and C.elegans proteins that are characterized to various extents.

	S.cerevisiae	S.pombe	C.elegans
Total number of known and predicted proteinsa	6145	4829	18 545
Proteins characterized by genetics or biochemistryb	3778 (61% of total)	889 (18% of total)	1541 (8% of total)
Proteins known by similarity to characterized proteinsc	701 (11% of total)	2384 (49% of total)	10 227 (55% of total)
Proteins of unknown functiond	1665 (27% of total)	1564 (32% of total)	7118 (38% of total)

^aTotal number of predicted proteins as of September 2000 (before completion of the S.pombe genomic sequencing effort).

^bProteins with experimentally determined function, role, subcellular localization, modification or protein–protein association, or with known mutant phenotypes beyond essentiality/non-essentiality.

^cExperimentally uncharacterized proteins with similarity to other proteins of known or predicted function, or containing domains or motifs of known function.

^dExperimentally uncharacterized proteins with no similarity to other proteins, or with similarity to uncharacterized proteins.