We had a seminar the other day on optogenetics given by one of the junior faculty in the neuro side of our department. Those of us in the biomechanics side of things are increasingly interested in the sensorimotor processing necessary to regulate the complex musculoskeletal behaviors we observe. Like good physiologists, we want to be able to disrupt the systems to see how they respond. And the prospect of being able to alter sensory and motor signals reversibly and quickly is particularly intriguing. So we had a chat about it.
Talking with the neuro people is a stark reminder of disciplinary boundaries. Our basic questions overlap on the matter of animal behavior, yet diverge in where we focus our explanatory efforts. To caricature, we examine behavior and musculoskeletal systems, and treat the brain as a black box, and the neuroscientists examine behavior and the brain, and treat the musculoskeletal system as a black box. So things we take for granted, they often are unclear on, and vice versa.
As we were discussing the background of optogenetics, the names of Chlamydomonas and Volvox, the green algae from whose genome the photosensitive ion channel genes have been extracted, came up. Because of my dillettantish path through biology, I have fair amount of botany, and a lot of taxonomy, in my knapsack. And that same wandering path included a pretty extensive flirtation with both cellular physiology, and neuroscience as an undergrad. As we discussed the various components of optogenetics, the light gated ion channels, the promoter sequences, the virus delivery vector, different questions popped into my head. Why did the algae have light gated voltage channels (I'm assuming some sort of phototactic behavior)? Where transposon sequences used to insert the genes into the neurone genomes, so that they would be replicated along with chromosomes, or were they left as free floating strands of DNA? Of course, in our group of mammalian biomechanists and neuroscientists, no one really knew the answers to those questions. And to be honest, they probably couldn't have pulled Volvox out of a eukaryote line up.
I often quip that huge amounts of knowledge about Mus musculus is held by people who don't give a damn about mice. Likewise, many of the people who know about Xenopus development probably know very little about frogs. Model organisms, translational focus and systems based thinking lead to extensive study of organisms that is oddly divorced from an understanding of the organism qua organism. Evolutionary biologists do this too. Systematists famously know little about the biological uses of the various structures they use to construct cladograms. In fact there was a time when such knowledge was considered harmful to establishing relationships, and systematists proudly touted their lack of knowledge about organism function. And molecular biologists have often been not much better regarding the organisms whose genomes they code.
And yet, here, with optogenetics, we have a technology that is born of in depth knowledge of the physiology of single celled algae, the reproductive chemistry of viruses, and the control of genetic expression at the cellular level in mammalian neurons. None of these things are trivial. All of them are products of long research programs within subfields of biology. (The discovery and understanding of transcription factors alone was a huge revolution in cellular genetics, and the histroy of our understanding of viruses and single celled algae is equally fascinating).
It is true that discplines are necessary to provide depth of understanding. It is also true, as Michael Hendricks recently pointed out, that interdisciplinary research assumes the existence of robust, vibrant, INTERESTING disciplines. But for this interdisciplinaryness to occur, there must be people with enough curiosity about what is going on in the neighboring silo to, well, see a possibility for coupling viral vector technologies with voltage gated channels from algae. And when the results of interdisciplinary research become ubiquitous within a field, there are potential risks in remaining ignorant about those aspects of your technique that come from a different scientific history and background.
Without a minimum of curiosity about what's going on in the silo next door, interdisciplinary breakthroughs are impossible. And without a minimum of curiosity about interdisciplinary breakthroughs, our understanding of things we do in our own fields is more black box that we might like.