According to Tokyo Agricultural University, Professor Obata and his colleagues have established a technique for producing functional eggs in vitro from undifferentiated germ cells in the embryo of mammals using mice, and the eggs born by this method are produced. After fertilization, it was confirmed that the cells normally grew as mice.
With conventional culture methods, the surrounding ovarian cells could not support egg differentiation as in the body, but Professor Obata and his colleagues found that there were more genes whose expression was controlled by estrogen than usual, and they were estrogen inhibitors. Was added to the culture medium to improve oogenesis.

　This research result is expected to be useful for elucidating the mechanism of egg differentiation and to increase the production of useful animals and rare animals.It was published in the Proceedings of the National Academy of Sciences, an institutional magazine published by the National Academy of Sciences, in July 2016.

　The Proceedings of the American Academy of Sciences was first published in 1914 and is one of the most frequently cited scientific journals in the world.The contents covered range from biology and physics to social sciences.
For the Best Paper Award, six papers that reflect scientific excellence and originality are selected from the papers published in one year.