Table 1.

Summary of genes required for gonad development.

Gene	Zebrafish	Mouse	Human
vasa	Important for germ line specification, survival, migration and maintenance, required for fertility in adult zebrafish [21]	Required for male but not essential for female during germ cell development, crucial for premeiotic differentiation in spermatogenesis [63]	Expressed in germ line, necessary for germ cell maintenance [64]
dnd1	Required for PGC migration and survival [20]	Expressed in PGCs, Dnd1‐knockouts lead to germ‐cell‐free, sterile gonads [65]	Has been identified ESTs and genomic sequences encoding closely related genes in human [20]
piwil1	Essential for germ line maintenance, unessential for germ cell specification and early maintenance [23]	Essential for spermatogenesis [66]	Expressed in spermatocytes and spermatids [67]
piwil2	Required for germ cell differentiation and meiosis [24]	Much more predominant in female germ cells than in males [68]	Expressed in testis or embryonic cells, also important for the pathological process of various malignant tumors [69]
nanos1	Essential for PGCs survival, indispensable for maintaining the oocyte production [27]	Not concerned with germ cells development, expressed in maturating spermatids and oocytes [70]	Important for mRNA translation within chromatoid body, represses apoptosis in human germ cells [71], [72]
tdrd12	Important for germ cell development and maintenance [26]	Important for spermatogenesis [73], [74]	Involved in spermatogenesis [75]
ca15b	Required for PGCs development in early embryos and perhaps has an important role in oogenesis [29]	No detailed information	No detailed information
dyrk1a	Overexpression will alters the expression of some important factors (e.g. piwii1), leading to dysplasia of PGCs [30]	Involved in the migration and maintenance of PGCs [76]	Associated with Down Syndrome, related to cell proliferation and has other multiple functions [77]
sox9a	Important for male testis determination [31], [35]	Reduced expression in the ovary and growing expression in the testis, heterozygous mutations do not lead to XY sex reversal [78], [79], [80]	Heterozygous SOX9 mutations cause partial or complete XY sex reversal in the context of the skeletal malformation syndrome campomelic dysplasia [81], [82]
dmrt1	Unessential for ovary development, indispensable for testis development [37]	Required for maintaining spermatogonial stem cells (SSCs) during steady state spermatogenesis, important for recovery of spermatogenesis after germ cell depletion [83]	Required for human testis differentiation, dmrt1 deficiency is related to focal testicular dysgenesis and sex-reversal [84], [85]
amh	Important for regression of Müllerian ducts, controls the balance between proliferation and differentiation of germ cells in males [38]	Involved in Sertoli cell development, facilitate the expression of regulating factors in spermatogenesis [86]	Impacts a variety of fundamental processes within the ovaries and testes [87]
ar	Interact with androgens, essential for male development and maintenance, key to spermatogenesis and maintenance of ovarian function [41]	Essential for male reproductive development and spermatogenesis [88]	Crucial for spermatogenesis, AR mutations lead to disorders in male reproductive and developmental [59]
hsf5	Essential for proper spermatogenesis and fertility in males [40]	Essential for spermatogenesis [89]	Expression of HSF5 protein is restricted to spermatocytes and round spermatids [90]
cyp19a1a	Encodes an aromatase limiting the rate of transformation from testosterone to estrogen,plays duple roles during sex differentiation in zebrafish [43]	No detailed information	Irregular expression related to the development of polycystic ovary syndrome (PCOS) [91]
foxl2	Crucial for ovary development and maintenance, foxl2a and foxl2b make a cooperation to conduct ovary development and maintenance [45]	Indispensable for follicular development and female fertility maintenance, continuous expression important for “ovarian somatic cells to testicular cells” transformation [92]	Required for granulosa cell development, mutations lead to granulosa cell tumors (GCTs) [93]
nanos2	A marker for germline stem cell, expressed in both ovarian and testicular pre-meiotic germ cells [47]	Expressed only in male gonocytes, inhibits meiosis and promotes male‐type differentiation [94]	Testis-specific, expressed in prenatal germ cells and late stages of spermatogenesis [95]
nanos3	Only found in oocytes, nanos3 mutants perform loss of <20um germ cells in juvenile ovary [47]	Important for germ cell development [96]	Expressed in embryonic stem cells, essential for maintaining normal germ cell numbers [97]
brca2	Critical for ovarian development [51], [52], required for the development of embryonic kidney podocytes [53], [54]	Limited information is available due to most homozygous Brca2 mouse mutants display severe embryonic lethal phenotypes [60]	Involved in FA, breast and ovarian cancer [98]
fancl	Important for ovarian differentiation and development [46]	Necessary for germ cell proliferation maturation of oocytes, but not for the proliferation or maturation of spermatogonia in adulthood [46], [58]	Involved in FA [99], [100]
cyp17a1	Required for ovarian differentiation and maintaining male-typical SSCs and mating behaviors [55]	Deletion of Cyp17a1 leads to infertility and sexual behavior defects due to the insufficiency of androgen [101]	Essential for the production of androgens and glucocorticoids, involved in prostate cancer [102]
cyp11c1	Necessary for oocytes maturation, testicular development and spermatogenesis [56], [57]	Involved in congenital adrenal hyperplasia [103]	Involved in congenital adrenal hyperplasia and abnormalities in gonad [104], [105]