Scaling properties of protein family phylogenies

TL;DR

This study reveals that protein and species phylogenies exhibit similar scaling behaviors, indicating universal evolutionary rules, and introduces a model linking robustness and evolvability to these patterns.

Contribution

It demonstrates the universality of phylogenetic scaling laws across gene and species levels and proposes a model connecting robustness to these scaling properties.

Findings

Protein and species phylogenies share similar depth scaling.

A simple model estimates the robustness needed to reproduce observed scaling.

Robustness influences the diversification limits of biological systems.

Abstract

One of the classical questions in evolutionary biology is how evolutionary processes are coupled at the gene and species level. With this motivation, we compare the topological properties (mainly the depth scaling, as a characterization of balance) of a large set of protein phylogenies with a set of species phylogenies. The comparative analysis shows that both sets of phylogenies share remarkably similar scaling behavior, suggesting the universality of branching rules and of the evolutionary processes that drive biological diversification from gene to species level. In order to explain such generality, we propose a simple model which allows us to estimate the proportion of evolvability/robustness needed to approximate the scaling behavior observed in the phylogenies, highlighting the relevance of the robustness of a biological system (species or protein) in the scaling properties of the phylogenetic trees. Thus, the rules that govern the incapability of a biological system to diversify are equally relevant both at the gene and at the species level.