Reference gene expression analysis within sample series 1: day 0 and 7. (A) Representative example of intra- and inter-group variance determination based on the coefficient of variation (±CV) based on EF1α expression. (B) Intra-group variance of all nine reference genes. (C) Inter-group variation based on the average transcript quantities as illustrated in (A). Quantities in (A) and (C) expressed as transcripts per 10 ng RNA. ±CV = (standard deviation/average) x 100%.