Figure 1. Electrophoretic gel pattern (A) of cyclin D1 cDNA standard and its competitor after competitive PCR, and the standard curve (B). Chronological changes in the expression level of cyclin D1 mRNA in mouse tongues at embryonic days (E) 11, 13, 15, 17, and birth as analyzed by competitive RT-PCR (C). Each point with its vertical bar represents the mean ± 1 SD of 5 samples. The vertical axis is expressed as a percentage of the mean value at E11.