Evolution: A Game That Never Stops with Martijn Schenkel
Martijn Schenkel is a postdoc at the University of Groeningen & Georgetown University and a part of the Paradox of the Organism project in the Modeling Agency Formally cluster. Martijn’s work deals with evolutionary genetics and selection on the level of individual genes, a field of study that raises questions about whether we can label the tiniest units of biological information as agents in their own right. The Paradox of the Organism project, headed by Manus Patten and Arvid Ågren, explores the “paradox” that smaller units within organisms (such as individual genes or genetic sequences) can occasionally work against the success and well-being of the organism itself.
What are your areas of interest, and why are they so interesting to you?
I come from an evolutionary biology background, so the whole thing I find interesting about that is it has a very strong explanatory power for what we see happening in nature, and a very strong predictive power for what the future holds. To me, its major appeal is that you go from very simple principles to very complex results. And the funny thing about it, I think, is that it has this tendency to produce complexity where you don't expect it. And that's what makes it fun. You know, like the game never stops. That's where my main affinity for evolution biology comes from.
How did you get involved in the Biological Purpose project?
When I did my PhD, I did it on transitions in sex determination, and so I read a bunch of papers on things like sexual conflict and sexual chromosomes. I knew a bunch of work by Manus Patten; a couple of his papers were some of my favorite papers I read during my PhD. Same applies to Arvid. I read a bunch of his work and I knew him from Twitter, actually. When I saw their advertisement for the postdoc, I was like, if I don't apply to this, I will regret it for the rest of my life, because it basically ticked all the boxes of what I wanted to do, like theoretical work, the philosophical touches, working with people whose work I know I like, and the international network and seeing different kind of research cultures.
What drew you to thinking about the paradox of the organism?
If we go way, way, way back to when I did my undergrad, I had this assignment on levels of selection and it basically blew my mind at that point, because I’d never thought about that question. But it really just showed a very different way of looking at the process of evolution. Like, if you've never thought about things like gene-level selection, then seeing gene-level selection and seeing how it explains so much of what we see in nature kind of makes you see it everywhere.
When I saw the advertisement for the postdoc, I really started thinking “Why does this actually work?” It's kind of taking that amazement that I had years prior and taking the next step in that thinking process. It doesn't really make sense when you think about it. So there must be things going on that solve that paradox and make the paradox non-valid in some way. But I couldn't come up with a quick answer to that question, “How would you solve it?” That's kind of the million dollar question. We know that this is an issue, but which factors go into making it an issue, and which factors go into resolving that conflict between gene-level selection and organism-level selection?
I know some of what you're doing involves kind of formalizing that model. Do you have any thoughts on how these models could potentially be useful to other researchers down the line?
Yeah, if you look at the work that we do it's really aimed at trying to figure out one particular conflict between different levels. And in the past, people have looked at things like group selection and group adaptation and tried to see things like bumblebees – like a beehive, for example – and to what extent they are coherent units. And that’s been a verbal debate. Nobody’s putting a number on that.
The idea we have is that we want to take the next step and see if you look at this level of conflict within a collective - in our case, an individual - at what point does the collective actually break down? And you can imagine that line of thinking also can apply on other combinations of levels. So again, if we look at a beehive, we see them as this coherent community that functions to serve the success of the hive and the queen, or whoever you want to ascribe it to. But there must be some point where the complex potential for conflict becomes so strong that that coherence must break down, and bees rather than being communal organisms actually turn back into solitary organisms.
What's your favorite example of the paradox of the organism?
I always found it paradoxical that if you look at the potential for selfishness to occur among genes, it seems so rare. But it feels like at the same time, we're just scratching the surface on a lot of it. If you look at things like mitochondria, which are maternally inherited, it's very well known that they have effects that are beneficial to females, but detrimental for males. That's something that we call the mother's curse. It works with females and it disregards its function for males because it never is transmitted through males. And that same inheritance pattern applies to things like chloroplasts in plants. But we have no evidence that chloroplasts have these kind of selfish effects. They tend to be very well-behaved. And there's no reason why they should do that more than mitochondria or less. But if we see it for one, but not the other, it just doesn't really make sense. I don't know why it's not there!