The urgency of the COVID-19 pandemic has pushed some unlikely scientists into the fray, including a forensic anthropologist and a conservation biologist, egged on by their frisky African gray parrot.
Since March, Liliana M. Dávalos and Angelique Corthals have been largely confined to the Long Island home they share with their bird, Algernon, who likes to ruffle her bright red tailfeathers in the background of video calls. In the midst of their isolation, the couple have launched two cutting-edge research projects that could influence how we prevent and treat coronaviruses, including the one driving the ongoing pandemic.
Earlier this year, Dávalos, Corthals, and their video conferencing collaborators received funding from the National Science Foundation to unravel the mystery of how differences in bat and human bodies shape our responses to viruses such as COVID-19. One project will look at the interplay between genes and the immune response in humans, mice, and more than 30 species of bats, to determine how organisms might mount a defense to viral infection. The other will investigate the structure of bat and human olfactory systems, to determine the role they play in hosting a virus.
The couple’s work may seem like just a drop in the flood of new research aiming to combat COVID-19. But for Dávalos and Corthals, getting the chance to contribute to this vital scientific pursuit is also the next evolution in a remarkable love story that spans three continents, numerous labs, and one global pandemic.
As a kid growing up in Belgium, Corthals had a million interests. She studied violin as a teenager; initially majored in Slavonic studies in college; and did a thesis on Virginia Woolf. But she found her most steadfast fascination was in the growing field of biological anthropology.
By the early 1990s, it was increasingly clear that advances in genetic sequencing promised to turn human remains into unprecedented portals into ancient cultures. Researchers like Swedish geneticist Svante Pääbo had just begun extracting DNA from Egyptian mummies, and Corthals was mesmerized by the discoveries. “I wanted an intimate relationship with people from the past,” she says.
Corthals pursued a Ph.D at the University of Oxford, in England, and took her skills to New York City. “Boldly, I marched to the American Museum of Natural History and gave HR my [resume],” she says. It worked: She got a job in its cryogenic frozen tissue collection.
Dávalos always knew she wanted to be a scientist. As a child in Colombia, she watched a documentary about Louis and Mary Leakey, married paleoanthropologists who made important discoveries about human origins. It inspired her to lead her own expedition in her grandparent’s backyard, where, to everyone's surprise, she turned up bones—the remains of someone’s dog.
Her willingness to get her hands dirty persisted as an adult. At the University of Valle in Cali, Dávalos majored in biology, and developed a passion for evolution and bird watching. But Dávalos wasn't sure what to do after graduation. She'd been rejected from a handful of graduate programs, and ended up working for a time in science communications.
Eventually, Dávalos got a call about her application to a joint Ph.D. program at the American Museum of Natural History and Columbia University. A researcher told Dávalos if she would agree to switch from birds to bats, she could join them in New York City. So Dávalos packed her bags and began work on the winged mammal, which received relatively little attention in the scientific community at that time. What she could not know then was that she had just taken her first big step toward the partnership of a lifetime.
In the early 2000s, Corthals was spending much of her time in the bowels of the museum, surrounded by stainless steel vats of liquid nitrogen. She was working in a cryogenic collection that aims to preserve tissues from thousands of species as a permanent record of the planet's biodiversity. Scientists, delivery workers, and graduate students dropped off new specimens collected all over the globe. But Corthals gravitated toward one scientist in particular—bat researcher Dávalos—who could never seem to get her paperwork in order.
“I was harassing her,” Corthals says.
“Not in a bad way!” Dávalos interjects. “In a professional way.”
Corthals’ incessant demands for completed forms gave way to conversations about Egyptology, genomics, and experimental cinematography. But their future was tangled up in other kinds of red tape.
When Corthals and Dávalos met, same-sex marriage was illegal in most states, including New York. The couple entered into a domestic partnership, but it offered limited protections, especially in the context of immigration. “If we had been a straight couple and one of us had become a resident, then there would have been a path for the other,” Dávalos says. But as a gay couple, each of them had to find their own way to stay in the United States or risk returning to separate continents.
Corthals and Dávalos eventually got green cards through their respective employers. And when New York State’s Marriage Equality Act took effect on July 24, 2011, they jumped at the opportunity to expand their rights. On August 5, Corthals grabbed two colleagues as witnesses and married Dávalos at the New York City Supreme Court. They worried that if they waited, marriage licensing for same-sex couples would be suspended, as had happened in California.
“People like Angelique and I, we don’t take things for granted,” Dávalos says.
Seventeen years, three marriage ceremonies, and two pending citizenship applications later, both scientists have come a long way in their careers: Corthals is now a professor of forensic anthropology and pathology at John Jay College of Criminal Justice, and Dávalos is a professor of conservation biology at Stony Brook University, where she runs her own research lab. But their scientific tête-à-tête continues.
“We’re not just married legally,” Corthals says. “We’re also married mentally.” Over dinner, they offer advice on each other’s research. Sometimes, when the others’ expertise is required, they collaborate. In 2012, for example, Dávalos used shotgun proteomics —a type of protein analysis common in cancer medicine—to help Corthals identify a previously unsequenced mycobacterium in a 500-year-old Andean Inca mummy.
Bat noses and goblet cells
This spring, their interests and expertise converged once again as the coronavirus was making its way around the world. Past research suggests that viruses related to SARS and MERS circulate in bat populations. By comparing the genomes and morphology of Homo sapiens and various bat species, the couple think they can understand how bats harbor such viruses without getting sick, while a similar pathogen can send a human immune system into a deadly overdrive.
Early in the pandemic, Corthals saw reports that many pandemic patients lose their sense of smell. She hypothesized that the virus might be targeting goblet cells, which secrete mucus in the respiratory system and digestive tract. These cells are “ground zero for viral entry.” Bats are often asymptomatic hosts of coronaviruses, but goblet cells in humans can provide an ideal environment for pathogens to multiply. In people, the virus ultimately kills infected goblet cells, which can trigger a cascade of symptoms, including widespread inflammation and COVID-19’s signature dry cough.
Fortunately, Dávalos’ former Ph.D. student Laurel Yohe is a leading researcher in bat olfaction. In addition to genetic data and tissue samples, Yohe collected some of the first and most expansive CT scans of bat noses during her time at Stony Brook. That allowed her to visualize the incredible diversity between different species’ olfactory systems, which can arc like Gothic cathedrals and curve like ancient catacombs.
At the time, Yohe never imagined her basic science research would be relevant in a public health crisis. Now, with backing from the NSF, she is using her treasure trove of data to identify physical factors that might influence the immune system’s response to a virus like COVID-19.
“We can start to really understand how the nose works," Yohe, now a postdoctoral researcher at Yale University, says. "It seems like a silly thing, but compared to vision or hearing, [smell] is a super under-appreciated sense, and it’s extremely complex.”
At the same time, Dávalos and Corthals have embarked on another NSF-funded research project with David Ray, an associate professor at Texas Tech University who studies molecular evolution, and Diana Moreno Santillán, a postdoctoral researcher. The team is trying to identify the genes involved in the immune system’s response to infection by looking at similarities and differences in the genomes of more than 30 species of bats. Next, they’ll look at how the species actually express those genes and whether amplifying or downplaying certain sections regulates an animal's immune response.
Both projects could influence conservation efforts and public health planning, not just for COVID-19, but for other coronaviruses that might emerge in the future. Corthals, Dávalos, and their colleagues—human and parrot—have made swift progress. Their first results should be released early next year.
And whatever life, immigration law, or laboratory science throws at them next, the couple will tackle it like they always do: together.