Andrew Letten is a 2015-16 CEHG Fellow, a Postdoctoral Research Fellow in Stanford’s Biology Department, and a member of the Tadashi Fukami Lab. He completed his PhD in 2015 with David Keith at the University of New South Wales in Australia, where he investigated the role of spatio-temporal environmental heterogeneity in maintaining species coexistence and diversity in plant communities in South-east Australia. Previously, he received a Masters of Environmental Science and Law from the University of Sydney, and a BSc (Hons) in Ecology from the University of Cape Town, South Africa.
This content has been transcribed from an interview that took place on Stanford campus Wednesday, October 14, 2015 with CEHG’s Director of Programs, Cody Montana Sam and Communications Manager, Katie M. Kanagawa.
Can you tell us a bit about yourself, personally and professionally?
Personally, I’m a kind of U.K./ South African hybrid. I was born in the U.K. but moved to South Africa when I was 14. I did my undergraduate at the University of Cape Town and majored in Ecology and Environmental Science. I originally was going to do Environmental Science, but I got exposed to all these Ecology and Evolutionary Biology courses and I went on a sharp tangent in that direction.
In the South African system, you do a separate honors research year, when you don’t do any coursework, you just do research. For that, I did a study looking at rodent pollination and specifically looking at whether this one plant species, Liparia parva, in the Cape floristic region was rodent pollinated. As part of that, I did a study looking at the genetic community structure of rodent-pollinated species, compared with a bird-pollinated sister species. (For those who may not know, rodent-pollinated plants are adapted to be pollinated by a mouse, so they grow along the ground, are drab looking, and have exceptionally yeasty nectar.)
Then I spent about five years in the wilderness, where I wasn’t sure that I wanted to do a Ph.D. I was scared to commit to a Ph.D., though I loved research. So I worked as an environmental consultant for a couple years and then as a science writer for an NGO called Arkive in the U.K. After that, I moved to Australia and decided to do a Ph.D. in Community Ecology.
What was it like transitioning from industry back to academia?
It was excellent. I think I always knew that I wanted to do research but, for whatever reason, I had this fear of commitment. As soon as I went back to research, I thought, “Wow, what have I been doing? This is what I love.” I love the inquiry, the fact that you dictate what you are interested in and if you have an idea, you can pursue it. You are a little bit beholden by funding and whatever, but you can pursue that feeling of trying to work things out. It’s like riddle-solving, you know like if you’re into riddles as a kid. It’s that same kind of satisfaction.
Which current research project best fits your interests?
My Ph.D. was pretty nebulous. I had a great advisor who let me run amok with different ideas I had. What I am most interested in is the maintenance of diversity within communities and where that diversity comes from. In the first chapter of my Ph.D., I looked at how temporal heterogeneity fosters species coexistence. I asked myself, to what extent does it promote species coexistence and maintain diversity or, conversely, how does it reduce diversity when variability becomes too extreme? There is this trade-off between the two. So that was a component of my Ph.D. and that’s a component that I’m bringing across to the stuff I’m going to be doing here, which is looking at the parallel effects of temporal and spatial variability on both species diversity and genetic diversity within species, using microbial communities as a model system.
How did you hear about the CEHG fellowship program?
I got in touch with Tad Fukami. I really wanted to work with Tad because he’s been doing this amazing work with microbial communities. For my Ph.D, I used a lot of existing observational data. By the end of my Ph.D., all I wanted was to manipulate something, as I hadn’t actually done experimental work. I’d done a lot of analysis. When you’re using someone else’s data, there are always these idiosyncrasies and little things that you think argh (laughs). So I wanted to do my own experiments. I wanted to look at some theoretical problems that were particularly amenable to studying with model systems. One of the things I was really interested in, getting more toward the genetics angle, is I wanted to look at the relationship between species-level diversity and genetic-level diversity.
In community ecology, we tend to look at species as the units we are interested in. Population geneticists are more interested in genetic variance. There’s actually surprisingly little marriage of the two. They get studied in parallel, despite the fact that the theory is analogous a lot of the time.
So there is this movement—and I’m not sure how much you would see it in population genetics, but definitely in community ecology—of borrowing theory from population genetics across to community ecology. Stephen Hubbel ported neutral theory across to explain species diversity (i.e. coexistence of lots of similar species). More recently, Mark Vellend at the University of Sherbrooke in Canada is pushing the idea of a theory of community ecology founded largely on the pillars of population genetics.
What lessons might you want to share with other people thinking of making a move to the States to pursue a postdoc in Genetics?
With academia, I would say do it because you really want to. In Australia, you get a lot of people coming through undergrad and going straight through to Ph.D programs. Unless they are super motivated, there’s a danger that they will burn out. People don’t always know that it’s what they really want to do, but at least know that it’s something that you really enjoy. Don’t do it for the sake of it.