The human gene encodes a protein containing one KRAB domain and thirty-four zf-C2H2 domains. Domain orders of chimpanzee homologous gene resembles human gene. Orangutan homologous gene and gibbon homologous gene resembles each other but both differ from human gene. We proposed they represent the ancestral state. Thus human and chimpanzee experienced their specific changes in their common ancestral lineage. Rhesus homologous gene differs from orangutan or gibbon. Either gain of sequences in rhesus lineage or deletion of sequences in the common ancestral lineage of orangutan and gibbon could be an explanation. The chimpanzee homologous gene and orangutan homologous gene human ZNF91 is manually predicted. The gibbon homologous gene human ZNF91, ENSNLEG00000026775, only exist before Ensemble version 90.