Cattle gene-edited to carry donor sperm
Scientists have discovered how to make male pigs, goats and cattle that can produce sperm containing the DNA of donor animals.
The technology could accelerate beneficial changes within an animal species that might occur over time with evolution, the study suggests.
Scientists say the advance could quicken the spread of desirable characteristics in livestock, such as resistance to harsh weather and benefit people in the developing word. However, they caution that more research is needed before it could be used in the food chain.
Improving livestock to boost food production for a growing global population is a long-standing aim for scientists.
Researchers led by Washington State University (WSU) and the University of Edinburgh’s Roslin Institute made their advance through gene-editing – a type of engineering that allows scientists to alter small parts of an animal’s DNA.
They used the gene-editing tool CRISPR-Cas9 to knock out a gene from DNA in a number of species including mice and cattle.
The gene – NANOS2 – is specific to male fertility and was removed in animal embryos that would be raised to become male surrogates.
The male animals – termed surrogate sires – were born sterile but began producing sperm after researchers transplanted stem cells from donor animals into their testes.
Sperm produced by the surrogate sires only carries DNA of the selected donor animals.
Surrogate mice mated with normal female mice and fathered healthy offspring who carried the genes of the donors. Larger animals such as cattle have not been bred.
The researchers say the technology could give breeders in remote regions better access to DNA from elite animals and allow precise breeding where artificial insemination is difficult, as in beef cattle and goats.
Currently, gene-edited surrogate sires cannot be used in the food chain anywhere in the world.
“This technology could boost food supply in places in the developing world, where herders still have to rely on local animals to improve their stock. This shows the world that this technology is real. We now have to work out how best to use it productively to help feed our growing population.”
“If we can tackle this genetically, then that means less water, less feed and fewer antibiotics we have to put into the animals. However, even if all science is finished, the speed at which this can be put into action in livestock production anywhere in the world is going to be influenced by societal acceptance and policy. By working with policymakers and the public, we can help to provide information assuring the public that this science does not carry the risks that other methods do.”
The research is published in the Proceedings of the National Academy of Science and was funded by the USDA National Institute of Food and Agriculture, WSU’s Functional Genomics Initiative and Genus plc.
The Roslin Institute receives strategic investment funding from the Biotechnology and Biological Sciences Research Council, as part of UK Research and Innovation.