Germ cells are vital for reproduction and heredity. However, the mechanisms underlying female germ cell development in primates, especially in late embryonic stages, remain elusive. Here, we performed single-cell RNA sequencing of 12,471 cells from whole fetal ovaries, and explored the communications between germ cells and niche cells. We depicted the two waves of oogenesis at single-cell resolution and demonstrated that progenitor theca cells exhibit similar characteristics to Leydig cells in fetal monkey ovaries. Notably, we found that ZGLP1 displays differentially expressed patterns between mouse and monkey, which is not overlapped with NANOG in monkey germ cells, suggesting its role in meiosis entry but not in activating oogenic program in primates. Furthermore, the majority of germ cell clusters that sharply express PRDM9 and SPO11 might undergo apoptosis after cyst breakdown, leading to germ cell attrition. Overall, our work provides new insights into the molecular and cellular basis of primate fetal ovary development at single-cell resolution.

生殖细胞对于繁殖和遗传至关重要。但是，在灵长类动物中，特别是在胚胎后期，女性生殖细胞发育的潜在机制仍然难以捉摸。在这里，我们对整个胎儿卵巢中的12,471个细胞进行了单细胞RNA测序，并探索了生殖细胞和利基细胞之间的通讯。我们在单细胞分辨率下描绘了两个卵子发生波，并证明了祖细胞在胎儿卵巢中显示出与Leydig细胞相似的特征。值得注意的是，我们发现ZGLP1在小鼠和猴子之间显示差异表达的模式，这与NANOG不重叠提示其在减数分裂进入中的作用，但在激活灵长类动物的卵母细胞程序中不起作用。此外，大多数强烈表达PRDM9和SPO11的生殖细胞簇在囊肿破裂后可能会发生凋亡，从而导致生殖细胞磨损。总体而言，我们的工作为单细胞分辨率的灵长类胎儿卵巢发育的分子和细胞基础提供了新见解。