Orthology established by Feijoo et al., 2004 (20 genes)

Orthology for irx1a ( Chr: 16 )
Orthology for irx1b ( Chr: 19 )
Orthology for irx2a ( Chr: 16 )
Orthology for irx3a ( Chr: 7 )
Orthology for irx3b ( Chr: 25 )
Orthology for irx4a ( Chr: 16 )
Orthology for irx4b ( Chr: 19 )
Orthology for irx5a ( Chr: 7 )
Orthology for irx5b ( Chr: 25 )
Orthology for irx6a ( Chr: 7 )