Oogonia are the cells that turn into primary oocytes in oogenesis. It is an essential process for oogenesis and spermatogenesis. Parthenogenesis can occur without meiosis through mitotic oogenesis. This would be caused by two non-disjunction events during oogenesis. The formation of an oocyte is called oocytogenesis, which is a part of oogenesis. The interactions between the fusome and microtubules result in cyst polarity in oogenesis. During oogenesis, the oogonia become primary oocytes. In contrast to oogenesis, the production of sperm cells is a lifelong process. Discontinuous oogenesis development patterns suggest that Patagonian toothfish do not spawn annually. During the primary oocyte stage of oogenesis, the nucleus is called a germinal vesicle. Primary oocytes will undergo oogenesis in which they enter meiosis. A number of ova are present at birth in mammals and mature via oogenesis. Sperm are produced by the process of spermatogenesis and eggs are produced by oogenesis. The food material and associated control structures are supplied during oogenesis. Oogenesis is greatly affected by pollen intake.