Orthology established by Mendelson et al., 2013 (6 genes)

Orthology for s1pr1 ( Chr: 22 )
Orthology for s1pr2 ( Chr: 3 )
Orthology for s1pr3a ( Chr: 22 )
Orthology for s1pr3b ( Chr: 21 )
Orthology for sphk1 ( Unmapped )
Orthology for sphk2 ( Chr: 16 )