Endogenous transcription levels of ol_pmp22 through medaka fish development. Relative transcription levels of total (A), 1A (B) and 1B (C) are shown. Total RNA was prepared from mixed extract of some fish at 4, 6, 8, 14 and 30 dpf, and was used as template for quantitative RT-PCR. Beta-actin transcripts were used for an internal control. Each relative transcription level was quantified by defining the average of 4 dpf transcription level as 1.0. (P < 0.05).