FIGURE 6

Transcriptome analysis of 10-dpf germ cells identifies the advanced germ cell proliferation as a sign of zebrafish female differentiation. (A). Gene ontology analysis of 668 differentially expressed genes (DEGs) upregulated in the 10 dpf W-hybrid. (B). The heat map of DEGs in the pathways of chromosome segregation (GO:0007059) and cell cycle (GO:0007049) are high in the W-hybrid at 10 dpf and gradually decreased at 12 and 14 dpf. The expression level is normalized by a z-score (C). The germ cell numbers of TL laboratory strain at 1, 8, 10, and 12 dpf. Germ cells significantly proliferate at 10 dpf. (D). The germ cell numbers of W- and Z-hybrid become different from 10 dpf on. (E). Germ cell number in ZW genotype of Nadia is higher than that in ZZ gonad at 10 dpf. (F). Double immunofluorescence showing PCNA staining for proliferating germ cell and Vasa (green) for germ cells. DAPI staining is white for nuclei. (G). Quantitation of PCNA⁺-germ cells, showing ZW gonads contain more proliferating germ cells than ZZ gonads at 10 dpf. One dot represents data from one gonad. The two-tailed and unpaired student t-test used for statistical analysis.