Faculty Notes



the Sunset

My greatest experience at Carnegie Mellon has been the interaction with my students — graduate students, research undergraduates and the students in the courses I taught.

On the cusp of his retirement, A. Javier López returned to his roots. During his 30 years at Carnegie Mellon University, López wore many hats in his lab — geneticist, biochemist, bioinformaticist — and taught a range of courses, including genetics and modern biology. But, just as he was set to retire, Carnegie Mellon launched a new program in environmental science and sustainability studies, and the Department of Biological Sciences planned to offer an ecology course. It turns out that López was just the man to help develop and teach it.

“When I was an undergraduate, I majored in biochemistry and minored in ecology. And I worked in tropical ecology during the summers with the U.S. Forest Service in the tropical forest in the Caribbean,” said Lopez, associate professor of biological sciences.

López taught the new ecology course in 2020 and 2021, and the course just added a new component — a field laboratory course in Costa Rica focused on tropical forest research. The first group of students spent eight weeks in Costa Rica last summer. López plans to join the students there in the future.

Even retirement can’t dim López’s dedication to undergraduate education.

“My greatest experience at Carnegie Mellon has been the interaction with my students — graduate students, research undergraduates and the students in the courses I taught.”

Over the years, López designed new courses and modified the curriculum in directions that he thought were important, especially with an emphasis on quantitative methods in biology. He was one of the co-instructors for the Phage Genomics Research course, a nationwide genomics course supported by Howard Hughes Medical Institute in which first-year students conducted authentic research.

Working with students in the lab, whether first-year students or graduate students, was one of López’s greatest joys.

“The students in my lab were fantastic,” recalled López, who mentored 12 grad students and dozens of undergraduates during his career. “They were smart and creative and fun to interact with. The atmosphere in the lab was always collegial and collaborative.”

In fact, that collaborative creativity led to one of the López lab’s biggest research contributions — the discovery of the mechanism of recursive splicing and how it’s used for the control of alternative splicing.

“I remember the very group meeting when we came up with the hypothesis. It was a group effort, graduate students, undergrads, we came up with it together, and together we figured out what kinds of experiments to do to test this hypothesis. It was really important, the way we all interacted in that discussion,” he said.

López’s discovery of recursive splicing solved a problem that had puzzled scientists for years — how a cell’s molecular machinery eliminates long introns without making errors.

“Javier came up with a solution that was completely outside-of-the-box and counterintuitive to what everyone was thinking,” said Biological Sciences Professor John Woolford. “He attacked the problem using ideas from molecular biology, genetics, evolution, and computational biology and bioinformatics. His thorough, broad and deep thinking led to a creative solution to an important, complicated problem.”

Outside of the lab, López was instrumental in shaping new directions for the department, specifically neuroscience and computational biology. He was the department representative when the Center for the Neural Basis of Cognition launched, and he led the searches for the first three neuroscience hires. He also was involved in starting the Lane Center for Computational Biology, which later became the Department of Computational Biology.

As he heads into retirement, López is excited to have more time to enjoy two of his favorite hobbies — biking and sailing. He’s already logged a 120-mile biking trip and has plans to travel to remote locations for biking events. An avid sailor and sailing instructor, López recently sailed around the Virgin Islands with his wife and two other couples. For López, after a wonderful 30-year career, he truly is sailing into the sunset.

■ Amy Pavlak Laird