PARSIMONY, HOMOLOGY AND THE ANALYSIS OF MULTISTATE CHARACTERS.

Area of Science:

• Evolutionary Biology
• Systematics
• Phylogenetics

Background:

• Transformation series describe nested sets of synapomorphies, indicating shared homology between adjacent states.
• Rooting the order with outgroup comparison is crucial for determining the level of homology (apomorphic or plesiomorphic).

Purpose of the Study:

• To establish a robust method for analyzing character state order in phylogenetic analysis.
• To critically evaluate existing methods for determining transformation series order.

Main Methods:

• A two-step process is proposed, utilizing similarity and congruence with other characters as primary criteria.
• This approach addresses the homology problem inherent in ordering character states.

Main Results:

• The proposed method effectively analyzes the order of states within a transformation series.
• Existing methods like transformation series analysis, non-additive analysis, morphocline analysis, and ontogenetic analysis were found to be insufficient as they do not consistently apply both similarity and congruence criteria.

Conclusions:

• Accurate determination of character state order is essential for understanding evolutionary relationships.
• The presented two-step method, incorporating similarity and congruence, provides a reliable approach for homology assessment in phylogenetic studies.