Embryo manipulation of the germplasm.

The development of the avian embryo is used to demonstrate the potential for future advances in genomic strategies. A mathematical model is derived to indicate the most useful approaches for using chimeras to access the chicken genome. A review of the way that germ cells are processed through the gonad highlights the need for such an analysis of cell kinetics and indicates that the right rudimentary gonad may also be a useful area for research into germ cell and stroma signalling. Studies on the B cells of the immunological system show that antibody diversity is achieved by gene splicing and that these cells are capable of inducing homologous recombination in a wide range of chromosomes. This property opens up a whole strategy for chromosome manipulation that may be particularly useful in exploiting the properties of the avian microchromosome system.