2019 Highly Cited Researcher Series: Luke Harmon

February 12, 2020


According to Luke Harmon, finding life on other planets is inevitable. He often wonders whether we can predict what we might find, based on what we know about life on Earth. Harmon is a professor in the Biology Department, and one of four faculty from the University of Idaho recognized by Web of Science Group as a highly cited researcher in 2019.

The Tree of Life

The majority of Harmon’s research involves macro-evolution, or evolution over long timescales. His central data source for this work is the tree of life—the phylogenetic model that shows how all species are related to each other. “You can trace any two species on Earth back to a common ancestor, and if you put all those patterns together, you get a tree that shows how you go from one species to the 10 million we have now.” Harmon and his team use statistical methods and information from the tree of life to learn about the forces that drive long-term evolution. He studies questions like, “how did these species form?” and “how did they get the traits that they have?”

Twelve years ago, IBEST helped coordinate the faculty search that ended up recruiting Harmon at the University of Idaho. He says, “if it weren’t for IBEST, I wouldn’t be here”. He also attributes the broadening of his research interests and collaboration to IBEST and the U of I. “When I came here, I started working on microbes, which I had never done before. I broadened my view of the tree of life based on my work with IBEST.” Even after twelve years, Harmon still finds inspiration and collaboration opportunities at IBEST. “IBEST is to me like an ideas lab. I like to hear about all the different research that people are doing and pull ideas from that. If I have a crazy idea, then the first place I’ll go to try to present it is IBEST.”

Citations, Tools, and Bias

Harmon doesn’t keep track of citations of his work, except occasionally to “check what things that I’m doing have the most impact on the field, and to figure out what to do next.” He knows that paying too much attention to citations can be counterproductive, acknowledging that “it’s nice to see people are paying attention to your work, but there is a deeper conversation about the meaning of what we do.” Much of Harmon’s work involves building and maintaining statistical tools for others to use, which is where many of his citations come from. “The citations mean that other people are using our packages to do things. Often, they’re using them in totally and unexpected ways that I wouldn’t have anticipated when we built the tools, so I get a lot of happiness out of that—providing tools.”

The Highly Cited Researchers list mostly reflects older research that has had time to generate more citations. Harmon’s most cited paper is software. “It’s a package called GEIGER that’s a part of R and still being actively used. It breaks because of the world changing around it, so it has to be constantly maintained, but it still generates a lot of citations.” Another of Harmon’s high-impact projects is software called OneZoom, a facto-phylogeny viewer. “It’s the only way I know of for anyone to look at the tree of life in their web browser. That website has had close to 2 million unique visitors, and it reaches out into society in a way that none of my other work does.” OneZoom was developed by James Rosindell when he was at the University of Idaho as a postdoctoral researcher.

Part of Harmon’s work is constantly maintaining the tools that he creates, but he still does research and publishes his findings as well. “We published a paper last year that created a little bit of a ruckus and I think will get cited a lot.” His paper showed that measures of how fast new species form are biased by the age of things you are comparing—looking over short timescales, you see high rates of speciation, but the longer the time period gets, the more those rates go down. “We found this pattern across every dataset that we looked at, and it’s a bit of a peculiar result. It suggests that there’s something systematically wrong with the way that we’re estimating these rates.” Harmon is now tackling the paradox of using microevolution to predict changes across large timescales. He says that the problem is actually the opposite of what many people think. “If we look closely, we see rapid evolution, and if we zoom out, we see less diversity that what we would expect. So, the Earth is less diverse than we might expect under that kind of model. It’s too easy to explain macroevolution. In fact, there are missing things out there that should be there.” He and his team are currently writing a paper synthesizing these complex ideas.

Telling the Story

What really drives me is trying to explain broad-scale patterns. Can we explain exactly why we have the amount of diversity that we have? And is that process predictable in any way?
Harmon has several projects in the works right now, including his rate-scaling paper and a web browser visualization tool similar to OneZoom, but for understanding trait evolution. He says, “what really drives me is broad-scale patterns.” While many people are trying to explain the huge amount of diversity on Earth, Harmon is more interested in explaining exactly why we have the amount of diversity that we do, and if that process is in any way predictable. “It’s inevitable that we’re going to discover life on other planets, and I wonder whether we can make predictions about what we might find based on what we know that’s happened on Earth so far.”

Throughout his years as a researcher, Harmon has dealt with plenty of obstacles. He tells the story of one of the more significant challenges in his career, “we had a barrier for a long time that had to do with closed data. My work relies on getting lots of data from different sources, and a lot of that data was locked up in publications that cost money to get.” He remembers only having access to a picture of the phylogenetic tree—not something he could effectively work with. “I fought pretty hard up against that for a while, and I was an open science advocate. Now I think the tables have turned, I can see in my career that particular obstacle has gotten cleared away mostly, and people will share their data much more readily than they used to.”

Harmon’s favorite part of what he does is connecting his research specialty to other people’s. “Students and postdocs come into my office and tell me about the biological systems that they work on, and it’s this astonishing collection of natural history facts about species that I’ve maybe never heard of. And we can figure out how to make the methods serve that purpose of the natural history and tell some cool story about how those organisms came to be.”

Citation Summary
Total Publications: 123
Total Times Cited: 11,721
Most-Cited Publication: GEIGER: Investigating evolutionary radiations (cited 1,847 times)

Highly Cited Researchers

Article by Katy Riendeau
IBEST Design & Marketing Coordinator