(A) Schematic of SP genes on human chromosome 2 and Sp genes on mouse chromosome 1. (B) Here, we use SP140 as a model protein of the SP family to show the high degree of evolution in these proteins and the importance of studying this family in both mouse and human. Mouse Sp140, human SP140, rhesus monkey SP140, and zebrafish SP140 amino acid sequences were aligned using ClustalW, which determined that there was 34.7% pairwise identity between mouse and human at the amino acid level. Sequence similarity was determined using the Blosum62 score matrix and a threshold of 1. A schematic of human SP140 with functional domains is shown above the alignment. The intrinsically disordered region (IDR) is indicated on the human schematic but is mostly absent in the mouse. Abbreviations: BRD, bromodomain; CARD, caspase activation and recruitment domain; PHD, plant homeodomain; SAND, Sp100, Aire, NucP41/75, DEAF-1 shared domain.