Using fluorescent in situ hybridization (FISH) method, a gene encoding the catalytic subunit of protein phosphatase type 1 gamma (PPP1CC) was mapped to human 12q24.1-q24.2, rat 7 q22, and mouse 10C. These results indicate that the PPP1CC is a member of conserved synteny group between rat chromosome 7, mouse chromosome 10 and human chromosome 12. These data and mapping data about other members of PP1 family show that in spite of the high identity of PP1 isoforms, each isoform is encoded by different genes which located on different chromosomes in human, rat, and mouse.