Fig. 2

Using live tracing to study the correlation between the initial PGC numbers and sexual development. a Representative images of PGC-less and PGC-rich embryos at 1 dpf (a1, a5), 5 dpf (a2, a6), and 7 dpf (a3, a7). b Representative images of PGC-less and PGC-rich larva fish at 11 dpf (b1, b4), 14 dpf (b2, b5), and 20 dpf (b3, b6). c Frequency distribution of PGC number at 1 dpf; two boxes with dashed frame label the selected population of “PGC-less” and “PGC-rich.” The lateral areas of gonads were calculated and were shown at the lower right corner of images in a and b. d The sex ratio in the population of PGC-less and PGC-rich embryos. e Confocal microscopy of small and big gonads at 20 dpf with Tg(piwil1:egfp-UTRnos3)^ihb327Tg transgenic fish. e1 Confocal image of small gonads. e2Higher magnification of a representative image of small gonad displaying combined channels of DAPI, F-actin, and EGFP. e3 Magnification image showing the nuclei of gonocyte in a small gonad. e4 Confocal image of big gonads. e5, e6 Higher magnification of representative images of big gonads displaying combined channels of DAPI, F-actin, and EGFP. e5 shows an example in which the germ cells have an irregular shape of nuclei; e6shows an example in which chromatin nucleolus-stage oocytes exist. e7 Magnification image showing cells with irregular shape of nuclei. e8 Magnification image showing that the nuclei of gonocyte were similar to the one in a small gonad