Analysis of cell cycle distribution of the cells comprising Haliotis discus hannai diploid (A) and triploid (B) larvae at two developmental stages. DNA contents of the cells derived from the larvae were measured by flow cytometry and the ratios of the cells in each cell cycle phases were calculated. No significant difference in cell cycle distribution was observed by developmental stage of the larvae regardless of ploidy status. After colchicine treatment, however, the portions of G0/G1 and G2/M phases were decreased and increased, respectively, regardless of both developmental stage and ploidy status. All values are expressed as mean ± standard deviation of three independent experiments. a,bDifferent letters indicate significant differences (p < 0.05). T: trochophore, V: veliger.