Functional annotation is the process of attaching biological information to a gene or protein sequence. The basic level of annotation is to use the sequence alignment tool BLAST to find similarities, and then annotate genes or proteins based on this. However, nowadays, more and more biological function additional information is added to the annotation system. Additional information allows manual annotation to distinguish genes or proteins with the same annotation. By sequencing many genomes, computational annotation methods for characterizing genes and proteins from their sequences have become increasingly important.