To infer when a human uncharacterized protein first appeared during human evolution, distributions of homologous proteins of a human protein across the five major taxonomic groups were analyzed. The “match pattern” was assigned to each human uncharacterized protein. For example, when matches were found in all the five taxonomic groups, the match pattern “OOOOO” was assigned. Likewise, the pattern “XOOOO” was assigned when there was no hit in the group 1 (non-animals) but there were hits in all other four groups.
Table 5 presents the distribution of match patterns. The human was treated as the group 6 because all the human uncharacterized proteins were found in humans by definition. There were 63 human uncharacterized proteins that had homologous proteins in all the five major taxonomic groups. Matches in non-animal clade indicated that these proteins evolved and existed before emergence of animals and were preserved in almost all animal taxa. Some proteins showed unexpected patterns. For example, 7 proteins showed the pattern “OOOOX,” indicating that there were matches in the groups 1 to 4 but not in the group 5 (non-vertebrate chordates). This can be interpreted either as the protein was lost in non-vertebrate chordates during evolution or simply the current RefSeq database does not contain proteins of this clade.
Other interpretation????? When there was a match in the group 1 (non-animals), the human uncharacterized protein must have appeared before evolution of animals. There were 79 proteins… among them, 63 were present in all the five major groups…
108 showed matches in the group 2,…. First appeared during bilaterian evolution