The future of transgenic farm animal production with emphasis on pigs

Transgenic livestock already play an important role as models for human diseases, for producing recombinant pharmaceutical proteins, and in the future may serve as donors of organs for terminally ill patients and tissues and cells in regenerative medicine to cope with degenerative diseases and ultimately might contribute to satisfy the increasing demand for valuable animal derived proteins for an ever-increasing global human population. The first transgenic livestock were produced in 1985 by microinjection of foreign DNA into zygotic pronuclei. Since then, significant progress has been made with regard to methods that permit efficient and targeted insertion of precise modifications in the complex mammalian genomes. This in turn will further enhance the development of transgenic livestock with well-defined genetically engineered chromosomal loci that are not affected by neighbouring chromosomal sequences and without integration of undesired DNA sequences such as antibiotic resistant cassettes that hinder products of these animals to enter the market. Here, we review the recent advances of the methodologies for the production of transgenic farm animals which will be important in meeting global challenges in valuable animal protein production and will open new horizons for biomedicine.