However, the fertile phenotype in the Tex14 knockout mouse model, in which females lacked IBs, suggested that the cyst structure might not be indispensable for oocyte fate determination and the cyst-dependent germ cell model might not be the only mechanism for the oocyte selection in mice (Greenbaum et al, 2009; Ikami et al, 2021). The gene discussed is TEX14; the disease is cyst.