Quantitative tests of general models for the evolution of development

Area of Science:

• Evolutionary developmental biology
• Comparative genomics
• Phylogenetics

Background:

• Several models, including the hourglass, adaptive penetrance, and early conservation models, propose different patterns of evolutionary change during vertebrate ontogeny.
• These models have historical roots but have only recently been subjected to quantitative analysis.

Purpose of the Study:

• To develop and apply quantitative phylogenetic approaches for evaluating models of evolutionary trends in ontogeny.
• To critically assess existing methods for model evaluation and propose a more accurate approach.

Main Methods:

• Development of novel quantitative phylogenetic methods to analyze developmental event data.
• Application of these methods to developmental data from 14 vertebrate species.
• Comparison of model fit using the new quantitative approaches.

Main Results:

• Existing methods for assessing evolutionary developmental models were found to be biased.
• The hourglass, adaptive penetrance, and early conservation models were found to be overly complex.
• A simpler model, positing increased evolutionary change between ontogenetically adjacent events, sufficiently explains the observed data.

Conclusions:

• The proposed quantitative phylogenetic approaches provide a more robust framework for evaluating evolutionary developmental models.
• Simpler explanations are preferred when they adequately account for observed patterns in evolutionary developmental biology.
• Evolutionary change in vertebrate ontogeny may be best characterized by a model of adjacent event transitions rather than complex stage-specific constraints.