Comparative genomic organizations of the MHC class II region in mouse, domestic cat, and human. Brackets (A–C) indicate gene segments in human, but absent in mouse and cat. (D) A human gene segment absent in cat. (E) A mouse gene segment absent in human and cat. (F) A mouse segment absent in cat. Three feline LINE1 elements and unconfirmed open reading frames (X) shown in Table 1 are not included in the three species' maps. Sequences with accession nos. AF110520, AF100956, AF027865, AF050157 for mouse and Z97183, Z97184, AL031228, AL049813, X02228, X03100, Z95437, Z81310, Z99705, Z84497, Z96104, X87344, Z84490, AL049729, Z80899, U92032, Z84489, AL049740, Z84814, AL034394 for human were used for this figure.