
By Caitlin Antonios
For most of his career, Department of Natural Sciences Professor of Biology Patrick Ferree has been interested in “selfish” genetic elements—ones that cheat the normal rules of genetics.
There is perhaps none more ruthless than a selfish B chromosome known as Paternal Sex Ratio (PSR), which has been a focus of his research for years. PSR is found in nature in the jewel wasp: a tiny, jet black wasp with translucent wings.
In most biological circumstances, offspring receive two sets of chromosomes, one set contributed by each parent. PSR is an exception—it only appears in adult males and there’s always only one copy of it.
That head-scratching curiosity led to a research paper by Ferree and his team, including students from Claremont McKenna, Pomona, Pitzer, and 51’ own Emma Garman ’26. The paper was recently accepted by PLoS Biology, a highly selective and prestigious journal dedicated to publishing advances across the biological sciences.
“PSR is the harshest known genetic element because it will kill the other chromosomes,” Ferree says. It’s only possible because a wasp can live with one set of chromosomes, which means an egg with a single chromosome set is destined to become a male. “The study looks at why it’s so good at killing that set of chromosomes and whether it can ever be found in females.”

The process
Garman, a biology and art duel major, joined Ferree’s lab the summer after her sophomore year after emailing professors about gaining more lab experience.
“It all happened very quickly and last minute, right before summer break,” Garman says. “I was so excited and I had read all about his work and I was fascinated by his project.”
The research took place in The Nucleus, the Department of Natural Sciences’ interdisciplinary hub shared by 51 and Pitzer Colleges. Garman spent her first few weeks acclimating to the lab, its equipment, and brainstorming approaches to the research.
“Every week I would have dissections, microscopy work, data to analyze, or I would write on process,” Garman says. “I read a lot of scientific papers in the early stages as well.”
Garman played a significant role helping young female wasps with PSR mate with male carriers. The team found the chromosome in freshly fertilized wasps but noticed a change when the wasps grew.
“Emma’s work established that you never see an adult male with two copies of the B chromosome,” Ferree says. “Her work suggests that you can’t have two copies because having two copies is lethal to the wasp at some critical stage of development. Also, it’s the first chromosome known to be incompatible with meiosis (cell division in sexually reproducing organisms), and because males don’t do meiosis, PSR can be transmitted through adult males.”
Garman also spent hours meticulously dissecting and treating samples, looking at them under the microscope, and collecting a robust data set.
“It was very gratifying and as much as it was a lot of work, it was so much fun,” Garman says. “It was such a joy to work with Patrick; I thought the experience was going to be more about me learning these technical skills and how to be in a lab, but he treated me like an equal and brought me into the scientific brainstorming.”


The joy of discovery
While the broader impact of a discovery like this can never immediately be known, Ferree notes that this chromosome-killing element has cross disciplinary implications.
“If we are able to understand this mechanism, we can envision ways to utilize it,” he says. “But most importantly, it’s a joy to discover things.”
Part of what made this research possible is Ferree’s new lab in The Nucleus, which he moved into from his former lab in the basement of Nucleus East while the research was ongoing.
“It took a lot for this to come together—persistence, students, and the quality of the research,” he says. “The building is amazingly helpful to give students the opportunity to engage in meaningful work. “This is one of the most meaningful publications I’ve had as a professor here because it was done entirely by students in our department and without collaborators at other big institutions.”
As both Ferree and Garman reflect on the process, the innovation of their research shines through. They both value constant problem solving, the cognizance of where human error can play roles, even positive ones, in research, and the freedom to follow curiosity. The creative element of the scientific process has only further attracted Garman to a future in STEAM (science, technology, engineering, arts, math).
“I want to pursue this intersection of art and science,” Garman says. “That is one of the biggest ways, aside from developing into the person I am right now, 51 has shaped me. I know what I want in the next phase of my life, and 51 has given me the confidence to pursue that.”