Scientists have successfully created animal surrogate fathers that carry only the genes of donor animals — nicknamed “super dads” — in a step forward for gene editing with potential implications for global food production.
Researchers from universities in the United States and United Kingdom produced male pigs, goats, cows and mice whose sperm carry the genetic traits of another male individual.
That means when these “super dads” breed, the resulting offspring are expected to carry all the male donor’s genes instead of the surrogate’s.
“With this technology, we can get better dissemination of desirable traits and improve the efficiency of food production,” said Jon Oatley, a biologist at Washington State University who led the research team, in a news release from the university on Monday.
“This can have a major impact on addressing food insecurity around the world. If we can tackle this genetically, then that means less water, less feed and fewer antibiotics we have to put into the animals.”
Here’s how the process works: First, the researchers identify the animal that will be raised to become a surrogate father. Before the animal is born, researchers use the CRISPR gene-editing tool to remove a fertility gene in the embryo.
The animal is born sterile but otherwise healthy, the news release said. Then, researchers take stem cells from a male donor, and transplant them into the surrogate’s testes — and the surrogate begins to produce sperm that only holds the donor’s genetic material.
When researchers bred the surrogate mice, the offspring carried the genes of the donor male — showing a “powerful proof of concept,” said the news release. The pigs, goats and cows haven’t been bred yet; the WSU team is refining the transplantation process, before taking the next step.
The study, published Monday in the Proceedings of the National Academy of Sciences, also included researchers from Utah State University, University of Maryland and the University of Edinburgh. It was supported by the National Institute of Food and Agriculture, a US federal government body, and other academic funding.
Implications for food supply
The findings could have big implications for the world’s food supply and food security as the global population continues to grow.
This method of breeding animals could potentially “improve production characteristics for generating meat, milk, and fiber for human consumption” on a global scale, the study said.
“This shows the world that this technology is real. It can be used,” said Bruce Whitelaw of the Roslin Institute of the University of Edinburgh in the release. “We now have to go in and work out how best to use it productively to help feed our growing population.”
The method also provides a more “natural” breeding process for livestock breeders and ranchers, according to the release. Instead of artificial insemination or selective breeding, which can require surgery or keeping the animals in smaller spaces, the new technology could allow the animals to roam and breed at their own pace — because when they do, the offspring will still have the desirable male donor genes.
The technology could allow ranchers to produce animals with enhanced traits — for instance, greater resistance to disease or better heat tolerance.
In particular, this discovery could impact the cattle industry, as it “opens the intriguing possibility of one day developing bull ‘super dads’ that then can be harnessed for disseminating desirable genetics in cattle populations around the world,” the study said.
It could be used to conserve endangered species
This new technology could also be used in conservation for endangered species, according to the study. When a species’ numbers dwindle, animal communities become isolated from each other and genetic diversity drops — something gene editing could address.
Scientists around the world have been racing to develop new technologies, ranging from in vitro fertilization (IVF) to cloning, to save a number of species from the mass extinction we’re currently in.
The rate at which species are dying out has accelerated in recent decades, one study found this June; about 173 species went extinct between 2001 and 2014.
In Ohio, researchers celebrated in February when they enjoyed a breakthrough of their own — a pair of cheetah cubs born from IVF to a surrogate cheetah mother for the first time. Further south in Texas, researchers successfully cloned a colt of the endangered Przewalski’s horse for the first time earlier this month, raising hopes of reviving the species, known as the last wild horse.
And in Malaysia, where every Sumatran rhino has died, scientists are hoping to use frozen tissues and cells to give birth to new babies using surrogate mothers.
The WSU news release heralded the scientists’ success as the “latest step in animal husbandry” — but this comes as companies and consumers push for more meat alternatives.
Greenhouse gas emissions from livestock represent 14.5% of all global emissions , according to the United Nations’ Food and Agriculture Organization. Livestock farming has such a large impact because cows emit methane, a potent heat-trapping gas. Raising livestock for food also uses a tremendous amount of land and water, some of which could be used to produce food more efficiently.
In the face of our climate crisis, many are calling for people to switch to plant-based diets and cut down on the massive cattle industry — instead of pushing forward with meat production, as the new study seems to propose.
The study could also attract controversy for a different reason: any advancement with gene editing technology inevitably raises questions of ethics, especially after a Chinese scientist reportedly created the world’s first gene-edited babies in 2018, prompting international backlash.
The news release acknowledged that its new surrogate sire technology faces obstacles in “government regulations and public perception.”
“Even when the technology is advanced enough for commercialization, gene-edited surrogate sires could not be used in the food chain anywhere in the world under current regulations, even though their offspring would not be gene-edited,” the release said.
“This is due in part to the misperceptions that gene editing is the same as the controversial gene manipulation, (WSU biologist) Oatley said,” according to the release. “Gene editing involves making changes within a species that could occur naturally. It does not combine DNA from different species.”