Evolutionary stochastic dynamics of speciation and a simple genotype-phenotype map for protein binding DNA

TL;DR

This paper develops a biophysical model of speciation based on co-evolution of protein-DNA binding, showing that smaller populations tend to speciate faster due to sequence entropy effects influencing phenotype space.

Contribution

It introduces a biophysically motivated approach to model speciation, emphasizing the role of sequence entropy and population size in divergence rates.

Findings

Smaller populations have higher speciation rates.

Sequence entropy influences population proximity to incompatible phenotypes.

Neutral hybrid diffusion occurs despite speciation dynamics.

Abstract

Speciation is of fundamental importance to understanding the huge diversity of life on Earth. In contrast to current phenomenological models, we develop a biophysically motivated approach to study speciation involving the co-evolution of protein binding DNA for two geographically isolated populations. Our results predict that, despite neutral diffusion of hybrids in trait space, smaller populations have a higher rate of speciation, due to sequence entropy poising populations more closely to incompatible regions of phenotype space. A key lesson of this work is that non-trivial contributions of sequence entropy give rise to a strong population size dependence on speciation rates.