Perinatal germ cell development and differentiation in the male marmoset (Callithrix jacchus): similarities with the human and differences from the rat

summaryanswer: In a process comparable with the human, marmoset GC differentiate rapidly after birth, losing OCT4 expressionafter 5–7 weeks of age during mini-puberty. what is known already: Most of our understanding about perinatal GC development derives from rodents, in which all gono-cytes (undifferentiated GC) co-ordinately lose expression of the pluripotency factor OCT4 and stop proliferating in late gestation. Then afterbirth these differentiated GC migrate to the basal lamina and resume proliferation prior to the onset of spermatogenesis. In humans, fetal GCdifferentiation occurs gradually and asynchronously and OCT4 + GC persist into perinatal life. Failure to switch off OCT4 in GC perinatallycan lead to development of carcinoma in situ (CIS), the precursor of testicular germ cell cancer (TGCC), for which there is no animal model.Marmosets show similarities to the human, but systematic evaluation of perinatal GC development in this species is lacking. Similarity,especially for loss of OCT4 expression, would support use of the marmoset as a model for the human and for studying CIS origins.