Structure trees and species trees: what they say about morphological development and evolution.

Area of Science:

• Evolutionary developmental biology
• Morphological evolution
• Developmental genetics

Background:

• Morphological evolution is typically linked to species evolution.
• Developmental genetic pathways can evolve independently, analogous to gene duplication.
• This can lead to incongruence between species trees and
• structure trees

Purpose of the Study:

• To propose that developmental pathways underlying morphology evolve akin to genes.
• To investigate the evolutionary history of morphological structures using a tree-based approach.
• To analyze leaf primordia evolution to understand developmental integration.

Main Methods:

• Morphological evolutionary analysis of leaf primordia.
• Construction and comparison of
• structure trees
• and species trees.
• Identification of developmentally integrated structures.

Main Results:

• Leaf primordia in monocots and relatives form a
• structure tree
• , indicating developmental integration.
• This tree structure breaks down within monocots, suggesting no single
• "monocot leaf primordium" entity.
• A distinct group of uniform monocot primordia, exemplified by maize and rice, was identified.

Conclusions:

• Developmental pathways can evolve independently, creating
• structure trees
• that may differ from species trees.
• Morphological structures can be evolutionarily maintained as integrated developmental entities.
• Analysis of
• structure trees
• enhances interpretation of comparative developmental and molecular studies.