Germ line transmission in transgenic mice.

Our laboratory has recently demonstrated the successful transfer of genetic material into the genomes of newborn mice by injection of that material into pronuclei of fertilized eggs. Our initial results indicated two patterns of processing of the injected DNA: one in which the material was not integrated into the host genome, and another in which the injected genes became associated with high molecular weight DNA. We now present evidence that these patterns are maintained through further development to adulthood. We provide definitive evidence of the covalent association of injected DNA with host sequences, and transmission of such linked sequences in a Mendelian distribution to 2 succeeding generations of progeny. The observation that injected gene sequences can become integrated and stably transmitted through the germ line should contribute significantly to further studies of this gene transfer system.