Transgenic farm animals: status of the current researches and the future

Abstract

The production of transgenic farm animals is of great interest of modern basic and applied researches. This article reviews methods for production of transgenic farm animals including pronuclear microinjection, nuclear transfer of genetically transformed somatic cells, retrovirus and lentivirusmediated gene transfer, the application of spermatogonia as a target for gene transfer. Using site-specific endonucleases (ZNF, TALEN, CRISPR/Cas9) as modern techniques allowing significantly to improve the gene transfer efficiency in farm animals are briefly described. The particular attention is focused on method for genetic modifications of chicken. The advances in various areas of genetic engineering domestic animals are discussed including creating animals with altered metabolism status to improve the quality and efficiency of production, which are genetically resistant to infectious diseases, producers of biologically active recombinant proteins, donors of organs for human transplantation(xenotransplantation) and animals-modelsfor translation biomedical researches. The innovative immune therapy assay as an example of practical application of transgenic animals-bioreactor technology is characterized.

Perspectives in Genome-Editing Techniques for Livestock

“…In several reports, it was described that primary goat fibroblasts could be successfully modified at 80–90% efficiency [ 29 , 50 , 51 ]. Fibroblasts with a diallel knock-out of the myostatin gene were used for SCNT, resulting in viable transgenic offspring [ 52 ]. One of the proposed ways to eliminate genetic mosaicism is the direct injection of the CRISPR/Cas9 system components into metaphase II oocytes or early zygotes.…”

“…In sheep and cattle, injection of CRISPR/Cas9 into zygotes reduces mosaicism more effectively than injection of metaphase II oocytes [ 2 , 54 ]. At the moment, fetal fibroblast-derived genetic modifications have been created for almost all types of farm animals, including cattle, pigs and goats, using the CRISPR/Cas9 system [ 29 , 52 , 55 , 56 ].…”