Fig. 3

Differentiation of gonads of XX and XY genotypes and male-biased expression of dmrt1 in fighting fish. A Gonad differentiation of XX and XY genotypes at 3, 5 and 12 days post fertilization (dpf), where scale bars indicate 10 μm. B Normalized coverage of mRNA reads mapped onto the dmrt1 locus, obtained by sequencing transcriptomes of pooled XX and XY genotypes at 3 dpf, where coding regions are shown above the graph in the black horizontal line. C Expression of dmrt1 in embryos and hatchlings of fighting fish at 1, 2, 3, 5, 12, 20 dph, and in gonads of adult male and female, analysed by reverse transcription PCR with gene-specific primers. House-keeping gene, β-actin, was used as positive control. Embryos with XY genotypes at 1, 2, and 3 dph were pooled for detection, while the other samples at 5, 12, and 20 dph were separately pooled for XX and XY genotypes. D Relative expression of dmrt1 in the same samples as in C, examined using quantitative real-time PCR. Expressions in mature gonads were quantified in individual samples (n = 3). Difference between males and females was examined using Mann-Whitney test (***, P < 0.001)