Recent Research in Germ Cells

Dear Colleagues,

Germ cells (gametes) are indispensable for sexual reproduction in animals and plants. They have a unique ability to transmit genetic information to the next generation. In many species, the female germ cells (oocytes/eggs) serve as a nutritional depot for embryo development. Male and female germ cells develop during an intricate process of gametogenesis from common germ-line precursors, acquiring sexual specificity at the structural and molecular levels. Because the ultimate function of female and male gamete differs (the egg supplies genetic material and nutrition for a future embryo, while sperm supplies the genetic material only), there is a drastic difference in the course and the outcome of oogenesis and spermatogenesis. While the oocyte acquires a set of specialized organelles, sperm loses many structures unrelated to motility and fertilization per se. Additionally, gamete formation requires a specialized cell division (meiosis), reducing the number of chromosomes before fertilization. In some species, female gametes are the only source of mitochondria (maternally derived mitochondria) for the future embryo. Thus, they develop the mechanisms for the selection of healthy mitochondria and the elimination of defective mitochondria. In many organisms, germ cells are produced continuously throughout life from the germ line stem cells. This is also true for mammalian spermatogenesis. In contrast, it seemed that mammalian females do not have germ-line stem cells and produce oocytes for a limited time. However, this dogma has been challenged recently. In this Topic, we invite original research and review papers covering any aspect of animal and plant germ cell structure and development, all aspects of female and male gamete specificity, and all germ cell-related diseases and therapeutic approaches.

Prof. Dr. Malgorzata Kloc
Dr. Jacek Kubiak
Topic Editors