Transgenic cows during milking
Transgenic animal technology has been largely developed in the mouse system, where it has reached a high degree of sophistication and allows the mouse genome to be modified efficiently and precisely.
The recent advent of somatic cell nuclear transfer has provided a route for cell-mediated transgenesis in livestock, and access to an entire toolbox for the purposeful engineering of livestock genomes.
Transgenic technology is highly versatile and, when applied to livestock, can be used for a wide variety of purposes ranging from biomedical (including producing human drugs, organs for transplantation and as human disease models) to agricultural applications (for improving food production and animal health, or reducing the environmental impact of animal farming systems).
The overarching goal of our research is to develop and evaluate transgenic technology for livestock applications to provide potential future options for New Zealand’s pastoral industries. Our research is centered around three main areas.
The first and major part of our research effort is aimed at the production of valuable recombinant proteins in the milk of transgenic dairy animals. Following the generation of proof-of-concept cows for this application (commonly known as 'biopharming'), we have entered into collaborations with industry partners to develop and commercialise so called ‘biosimilars’ - equivalents for approved human therapeutic drugs that are produced in the milk of transgenic dairy animals.
The second area of interest explores transgenic strategies to improve food products from livestock that are safer and healthier for human consumption. We are particularly interested in improving the composition of milk and associated dairy products, by either adding new or increasing existing beneficial components or reducing undesirable milk proteins.
Thirdly, we are interested in improving the predictability and safety of the technology. Main concerns have been the insertion of transgenes at random sites of the genome and the presence of antibiotic selection markers in the animals. These can be avoided by applying site-specific strategies such as recombinase-mediated and homologous recombination. While they are presently hampered by low efficiencies, we are evaluating the potential of novel targeting vectors and the introduction of site-specific DNA double-strand breaks by zinc-finger nucleases to increase the feasibility of targeted livestock genome modifications.