Inaba et al.(1992) used murine cDNA clones for 3 cyclin D genes that are normally expressed during the G1 phase of the cell cycle to clone the cognate human genes. D-type cyclins(cyclins D1, D2, and D3) are regarded as essential links between cell environment and the core cell cycle machinery. cyclin D2(CCND2) gene ia assigned to 12p13.