THE POSSIBILITY TO ALTER THE GENETICS OF DOMESTIC ANIMALS AND FISH IN A PREDICTABLE MANNER IS CLEARLY VERY ATTRACTIVE :
- SCIENTIFICALLY, THIS RESEARCH SHOULD CONTRIBUTE TO A BETTER UNDERSTANDING OF A FOREIGN GENE IN THE GERM LINE OF ANIMAL,
- TECHNICALLY, IT SHOULD IMPROVE THE PRACTICAL METHODS OF TRANSFER.
- ECONOMICALLY, IT SHOULD PROVIDE A SHORT CUT FOR THE IMPROVEMENT OF THE GENETICS OF ANIMALS, FOR INSTANCE IN OBTAINING ANIMALS GROWING AT A FASTER RATE.
Genetic characteristics of domestic animals can be rapidly modified through the transfer of deoxyribonucleic acid (DNA) to fertilized ova and the development of transgenics. Biological fluids (milk, blood, egg white, etc) of transgenic animals can be an abundant source of well matured proteins of clinical and veterinary interest. These goals can be reached if specific genes, promoters and vectors are prepared, and if methods to obtain transgenic animals in various species are defined.
Recombinant genes containing different promoters and growth hormone genes were prepared and tested in cultured mammalian and fish cells and in whole transgenic salmonids. Most of the regulatory elements from mammalian genes when tested in fish cells or in fish worked only on low levels. Fish genepromoters seem to be a better choice for the future. Several fish genes were cloned and characterized. Rabbit milk and bovine complementary deoxyribonucleic acid (cDNA) and genes were isolated and sequenced. Recombinant genes containing milk gene or bovine liver gene promoters and reporter genes were expressed in mammary cells in vitro and in transgenic mice. Retroviral vectors from birds were prepared. These vectors harbouring foreign genes transfer efficiently to chickens. Conditions were established for the efficient recovery of fertilized bovine ova, their microinjection, in vitro culture and transfer to recipients, with a high rate of survival. Finally, protocols were established for efficient generation of transgenic fish.
TWO STRATEGIES WILL BE USED TO INTRODUCE A NUMBER OF GENES INTO THE GERM LINE OF THE ANIMALS :
- MICROINJECTION OF DNA,
- DELIVERY OF THE DNA BY RETROVIRUSES.
THREE GENES ARE ALREADY AVAILABLE : MOUSE METALLOTHIONEIN, AND THE MMTV AND SV40 PROMOTERS. IT IS PROPOSED TO CLONE PROMOTERS FOR : HIGH LEVEL OF CALF PROTEIN SEQUENCE, HIGH LEVEL OF A SALMON PROTEIN SEQUENCE, THE RABBIT CASEIN PROMOTER AND THE SALMON AND BOVINE GROWTH HORMONE PROMOTERS.
Funding SchemeCSC - Cost-sharing contracts