ABSTRACT
The production of transgenic animals requires genetic modification of cells that retain ability to be incorporated into the germline and produce sperm and eggs. This chapter reviews the achievements in embryo manipulation that have given this strategy enormous potential and will describe the techniques that have yet to be developed in order to fulfil the potential for germline chimeras as intermediates in the production of transgenic chickens. The production of transgenic chickens using blastodermal cells is facilitated because the presence of somatic contributions from the donor provides an index of the success of the injection at the time of hatch. The relative efficacy of producing transgenic chickens using blastodermal cells or primordial germ cells will depend upon the time required to produce germline chimeras from them. The production of transgenic chickens via chimeric intermediates would be facilitated if the ability to proliferate blastodermal cells or primordial germ cells in culture while retaining their ability to colonize the germline were available.
