Gene Ontology annotation of annotated unique sequences (singletons and contigs) from P. margaritifera. Distribution (%) of gene ontology terms among the annotated unique sequences. GO ontologies are represented as general function categories. Among the 10 004 unique sequences with GO assignation, 5976 (59.7%) are involved in biological processes (A), 6855 (68.5%) have molecular functions (B) and 5737 (57.3%) are cellular components (C). Specialized terms of the binding category repartition (D) shows 17% of sequences implicated in ion binding.