Pig 135 snuffles and grunts inside his pen. Jon Oatley reaches through the bars to pet the more than 500-pound genetically modified animal.
“People have this image in their head of a pig with deformities, but they’re just normal pigs,” says molecular biologist Oatley ’01 MS, ’04 PhD as he rubs the pig’s ears.
The enormous, three-year-old pig is one of a handful bred by Oatley, director of WSU’s Center for Reproductive Biology, and his team to be surrogate fathers. Through genetic tinkering, Pig 135 is able to produce sperm that contains the genetic material of another pig rather than his own. This modification makes it faster and easier to breed pigs with desirable traits.
To modify a pig like Pig 135, it all starts with a single cell.
Using a gene editing process called CRISPR-Cas9, Oatley and his team of researchers are able to introduce a change to the DNA in a male pig embryo before it is implanted into a surrogate sow. Cas9, an enzyme that acts like a pair of scissors, is used to cut the DNA at a location of Oatley’s choice.
The cell then tries to repair the strand of damaged DNA, either by adding a new sequence or deleting a sequence. In this instance, the change causes the pig to be sterile when it reaches adulthood.
“It’s a mutation that could’ve occurred in nature,” Oatley says. “Nothing foreign was added.”
Mutations like red hair, blue eyes, and freckles in humans, and coat color and stature in dogs were created in a similar fashion, except the genetic changes were driven by environmental pressure and selective breeding rather than the hand of a scientist.
With CRISPR-Cas9, Oatley and his team can speed up these processes to eventually breed food-producing animals that are bigger, more resistant to disease, and require less food and water.
“We can do it in a single generation instead of over thousands,” Oatley says.
Once the modified pig reaches adulthood, Oatley’s team can inject it with stem cells from another pig with more desirable traits, allowing the modified pig to produce sperm with the elite pig’s genetic material rather than its own, making it a surrogate father.
Samantha Noll, a bioethicist on Oatley’s team, says animal welfare is the first thing the team focuses on.
“During all stages of the research process,” says Noll, “the researchers are discussing ethical and animal welfare implications.
“They’re working to address these big problems like hunger, security, disease resistance, and they’re also taking the time to ensure that they don’t create other problems during the research process.”
When the research team eventually breeds new animals, Pig 135 and his brethren will be euthanized to make room. But instead of their bodies being used to feed the hungry, they will be incinerated—as is fitting for an animal labeled as a biohazard under current regulations.
“He can’t even be composted,” Oatley says. “It’s the fear factor.”
Noll says the label is just a precaution.
“We’re following the most stringent requirements now, just in case, that way we don’t have an environmental impact that was unforeseen,” Noll says.
Oatley says there’s no experimental evidence it would be unsafe for humans to eat Pig 135 or others modified like him, but the process still raises ethical issues.
“We’re doing things that Mother Nature never intended us to do, but it has to happen at some point or we won’t be able to persist with the rate that human population is expanding,” Oatley says. “It’s a trade-off.”
As food insecurity continues to be a problem in both developed and undeveloped nations alike, Oatley says he and his team hope that by modifying pigs and other livestock, they can improve access to food for people today and in future generations.