Figure 2

Sex differentiation in grayling. Frequencies of fish with undifferentiated gonads (grey bars), gonads with testicular tissue only (blue bars), the testis-to-ovary phenotype (orange bars), and ovaries only (red bars) for the second experiment (sampling periods between 51–163 dpf) when phenotypes were determined by histology, and in the first experiment (sampling period at 237–245 dpf) when phenotypes were determined by morphology. The numbers in the boxes give the total sample sizes for the second experiment, and the number of fish that were both phenotypically and genetically sexed for the first experiment. The blue and red background colors indicate the overall frequencies of genetic males and females, respectively, for each of the two experiments. Phenotype and genotype matched perfectly for the first experiment (sampling period 237–245 dpf). At the last two sampling periods of the second experiment (135 dpf and 159–163 dpf), all fish with undifferentiated gonads had the male genotype, 3 of 5 individuals with testes had the male genotype, all other individuals had the female phenotype. See Table 2 for the match between phenotype and genotype at sampling periods after 135 dpf and Fig. 3 for examples of the various developmental stages.