In order to get a closer insight in the process of sequence annotation, 100 sequences from each of the ccl1, pfl and min datasets were manually reviewed by scientists actively working in the study of the different species. The curation process involved eight out of the 11 basic annotation styles (default style was only considered at Gow = 5, see Table 2) and proceeded through a direct revision of BLAST and annotation results. For each query sequence the following aspects were documented: number and taxa of different species spanned in the BLAST result (in a maximum of 20 BLAST hits), consistency of gene product descriptions through different hits, number and coherency of annotated GO terms on the light of current expert knowledge and/or available literature over the hit sequences, ratio between correct-declared and wrong/doubtful-declared annotations, GO term type and hit of origin in case of wrong-declared annotations and a global evaluation of the correctness of the annotation. As a working procedure, the described evaluation was applied to the Blast2GO default annotation style (default, Gow = 5) and the remaining seven annotation types were compared to the standard for their increase or decrease in annotation correctness and coverage.