Development, differentiation and manipulation of chicken germ cells.

Germ cells are the only cell type capable of transmitting genetic information to the next generation. During development, they are set aside from all somatic cells of the embryo. In many species, germ cells form at the fringe of the embryo proper and then traverse through several developing somatic tissues on their migration to the emerging gonads. Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. Unlike other species, in avian embryos, PGCs use blood circulation for transport to the future gonadal region. This unique accessibility of avian PGCs during early development provides an opportunity to collect and transplant PGCs. The recent development of methods for production of germline chimeras by transfer of PGCs, and long-term cultivation methods of chicken PGCs without losing their germline transmission ability have provided important breakthroughs for the preservation of germplasm , for the production of transgenic birds and study the germ cell system. This review will describe the development, migration, differentiation and manipulation of germ cells, and discuss the prospects that germ cell technologies offer for agriculture, biotechnology and academic research.