El concepto de homología filogenética y la selección de caracteres taxonómicos

Abstract

The practical problem of selecting taxonomic characters not only requires an extensive empirical basis. It also demands an examination of theories and epistemological principles behind character analysis. This review argues that character selection is equivalent to elaborating and evaluating hypothesis of homology. Based on a phylogenetic concept of homology as historical continuity among features or events in different organisms, a taxonomic character is viewed necessarily as a system of at least two homologs (character states). Hennig principle postulates that apomorphic shared states (synapomorphy) constitute the only justified evidence to recognize taxonomic groups. Epistemological principles for the recognition of homology (characters) include empirical and logical arguments. Empirical bases are similarity, conjunction and discrete, heritable and independent variation. A logical argument for evaluation of homology is the search for character congruence by means of the principle of inferential parsimony. This theoretical background reveals that hypothesis of homology are a result from an inference process, therefore homology statements logically depend on a specific data set and a particular cladogram. The phylogenetic concept of homology and epistemological principles reviewed here apply to all character systems, including those from biomolecules such as DNA. Procedures and technology for obtaining each character type will vary, but the basic ontology for their analysis is the same.

Keywords

• análisis de caracteres
• parsimonia
• sinapomorifas
• filogenia
• epistemología