A little update! I know it’s been an incredibly long time since I’ve posted on SoaC, primarily because I’ve been expanding my science communication on platforms like TikTok and Youtube. I’m also taking a new faculty position at St. Louis University in the Neurology department next month, where I’ll have the opportunity to do even more research. St. Louis is my hometown, so I’m looking forward to being back! Go, Billikens!

But this summer, I wanted to take time to dive back into the blog and do a little more writing, since it’s an artistic medium that seems to be rapidly falling out of favor online. (As a former-English-major-turned-scientist, that pains me to my core!)

So, to dip my toe back into the proverbial water, I thought I’d talk about my most recently published paper, The Molecular Basis of Punctuated Equilibria: The Roles of Developmental Genes in Stasis and Speciation. Now, for those of you who follow me primarily for topics like autism and Ehlers-Danlos syndrome, you may not know that I also study evolutionary biology and genomics– not only focusing on autism-related genes but also nervous system and developmental genes in general. For instance, you may have seen my video on the Cambrian Explosion of Autism Genes on Tiktok or Youtube, and that popular video was borne out of that facet of my work.

A few years ago, I had the honor of being a keynote speaker at the celebration of the 50th anniversary of Punctuated Equilibria (PE or “Punkeek”) and my paper is part of the special issue in the journal, Paleobiology, marking that important conference. I will say that, perhaps more than any of my other published work, this is the manuscript I’m most proud of, since it was a several-years-long labor of love. It went through many iterations and a few major overhauls to boot and I’m pretty pleased with the outcome. (Niles Eldredge also offered presubmission feedback, which was incredibly valuable and I’m super grateful to him!)

Hopefully, many of you have heard of the theory of Punctuated Equilibria, but just in case you haven’t or you don’t exactly recall what it is, here’s a recap: In 1972, Niles Eldredge and Stephan Jay Gould published a bombshell paper, Punctuated Equilibria: An Alternative to Phyletic Gradualism. Up until that point, most scientists believed that evolutionary change occurred at a slow, plodding, constant pace. What was so different about Eldredge and Gould’s new theory was that it showed that the fossil record typically didn’t support this slow, gradual mode of change; instead, there were non-directional fluctuations but for the most part, a species was relatively stable (in equilibrium) for most of its evolutionary “life” and when change did occur, it seemed to be relatively rapid (i.e., “punctuated”). So, there are long periods of stability (stasis) bookended by punctuated periods of change. This is typically what we see in the fossil record over time.

In classic fashion, scientists argued over Punkeek vs. Gradualism for decades. And one of the missing elements opponents sometimes cited was a genetic mechanism that predicted these stop-and-go patterns. That’s where my work comes in. Back in 2020, my colleague, Miriam Konkel, and I proposed the Developmental Gene Hypothesis (DGH), which we believed provided exactly that missing mechanism. Namely, developmental regulatory genes, which have a really strong influence on physical development (and which in turn would most likely be reflected in the fossil record), are a prime mechanism for those stop-and-go patterns precisely because they are very mutation intolerant. In short, they don’t like to change and so they are likely key to those long periods of equilibrium. However, when there’s enough pressure placed on them and their interacting networks, they do change and sometimes rapidly so. There’s the “punctuated” part for you.

In my newest paper, I significantly expand on the DGH and, what’s more, I provide mathematical modeling and simulations based on game theory (Nash equilibrium) to show how groups of interacting developmental genes maintain that stability but also “weigh anchor” quickly when placed under strong enough pressures. The idea behind Nash equilibrium in a mock game of several “players” (in this instance, genes) is that no single player benefits from changing their strategy (gene expression) when the behavior of all other players in the game remains the same.

Now, if you’ve managed to get this far in the blog you might be sitting there wondering, “I’m interested in autism. Why should I care about Punkeek, Nash equilibrium, and all these developmental genes???” Well, many autism genes are developmental genes– but on STEROIDS. If developmental genes are sensitive to mutation and don’t like to change much, autism genes are INCREDIBLY sensitive to mutations and abhor change. Ironically, that’s quite autistic of them!

But because they are extreme examples of this general trend, they may well be interesting sites for accelerated evolution as well. This in my mind makes them incredibly fascinating, not only for our anthropocentric (human-centric) purposes, but for evolution in general.

More to come in future. Stay tuned!