Animal geneticist Alison Van Eenennaam has six calves that are rather unusual. Most people might not pick up on what’s odd, but close inspection, and knowledge of bovine genetics, reveals that none of the calves have horns despite being a mix of breeds that typically have them. Even more surprising? The calves’ hornless state wasn’t bred into them — Van Eenennaam and her colleagues edited their genes using the new CRISPR technology.
The CRISPR gene editor uses an enzyme like a pair of scissors to cut DNA strands. Researchers can then insert whatever gene they select into the break. The technology is still in its early days, but it has experts seeing a future where gene editing can treat diseases or create crops better equipped for a changing climate.
Van Eenennaam, a researcher at University of California, Davis, operates at the forefront of biotechnology in animal agriculture. Dairy farmers customarily remove horns when their animals are still calves. The process is painful, but it spares the animals and their handlers from being gored in the future. Genetically hornless dairy cattle would no longer be subjected to dehorning. That’s only one way that Van Eenennaam is changing the game in agriculture and shaping the animals we eat. And she’s just embarked on an ambitious project that could help shrink the environmental footprint of the beef industry.
I’m not going to let the fearmongers dominate the conversation.
Van Eenennaam, 54, grew up as a “horse-mad” city girl in Melbourne, Australia, getting her equine fix visiting her aunt’s farm in the country. With stellar marks in school, she could have become a doctor or lawyer, but she chose to study animal science at the University of Melbourne. “It was right after Norman Borlaug got his Nobel Prize for the breeding associated with the Green Revolution in crops,” she says. Seeing daily coverage of the devastating famine in Ethiopia spurred Van Eenennaam to pursue agriculture as a way to make a difference.
As an undergraduate, Van Eenennaam spent time at a ranch in Texas, looking for practical experience to balance her academic work. She grew to love the Santa Gertrudis cattle there, and she mended fences with a ranch hand whose South Texas drawl was as impenetrable to her as her flat Australian vowels were to him.
Van Eenennaam still enjoys bridging cultures in a liberal California university town as a researcher who works with staunchly conservative landowners in the San Joaquin Valley. “I feel I don’t really belong in either place,” she muses, “but I can kind of see everybody’s side on issues.” With a mane of silver-white hair, an assertive jaw and mirthful blue eyes, she looks the part: somewhere between rancher and scientist.
Not surprising for someone accustomed to moving among disparate groups, communication is a strength for Van Eenennaam. “She can present complex concepts in a way people understand,” says Juan Medrano, an animal geneticist at UC Davis and adviser on Van Eenennaam’s master’s and Ph.D. work. “She is always concerned with finding the truth.”
Those skills have served her well — starting with the heated debates on the merits and risks in using genetically modified organisms for food. After a study came out that erroneously claimed GMOs caused tumors in rats, Van Eenennaam appeared on The Dr. Oz Show to try to separate misinformation from fact. Although gene editing uses different technology from the genetic engineering that creates GMOs, she is certain that people will conflate the two. “We have to speak up,” she says of scientists. “We’re the people who know how it could be useful and how incredibly valuable the tool is. I’m not going to let the fearmongers dominate the conversation.”
Hornless dairy cattle is one use of gene editing that Van Eenennaam thinks people could get behind. Her six calves at UC Davis are among the first bovines with dairy genetics that carry a beef cattle version of the polled gene, inserted with CRISPR, that makes them hornless.
While she monitors their progress, Van Eenennaam is also occupied with using CRISPR to gene-edit beef cattle as part of an early-stage, U.S. Department of Agriculture–funded project. It relies on the power of a gene called SRY that gives rise to testicles and testosterone production while inhibiting female characteristics. If a female with XX chromosomes carries the SRY gene on one of the Xs, that’s enough to give her all the physical characteristics of a male.
In beef cattle, that means more meat on an animal that grows faster than unedited females. Only a fraction of the industry’s cattle would have XX chromosomes with SRY because the gene editing makes these XX animals incapable of breeding, and beef producers will still need a certain number of unedited females. Yet given that there are more than 90 million beef cattle in the U.S. alone, it’s a project that has caught the attention of producers.
Right now, Van Eenennaam and her team are trying to “knock-in” the gene in a specific location on the X chromosome in bovine cells. Then, they can clone those cells, grow an embryo and get an animal with the SRY gene on an X chromosome. So far, the knock-in method has been successful with about 10 percent of their cells — which isn’t enough. When we spoke in mid-March, the latest round of cells didn’t have the knock-in gene in the right location. “It’s a disappointing result, but that’s science 99 percent of the time,” Van Eenennaam says.
If anyone has the grit to see a challenging project to fruition, it’s Van Eenennaam. Ronnie Green, animal geneticist and chancellor of the University of Nebraska-Lincoln, recalls meeting her in the early 2000s as a new faculty member at UC Davis. “I was kinda blown away by her, to be honest,” he says. A few years into their acquaintance, Green told Van Eenennaam that he could see her becoming a leader in the application of biotechnology to livestock. “She has become that in every shape of the word,” he says.